Immunohistochemical evidence of melatonin protection on lung tissue during chemotherapy / Evidencia inmunohistoquímica de la protección de la melatonina en el tejido pulmonar durante la quimioterapia

SUMMARY: The present study investigated the possible protective effects of melatonin on Bleomycin, Cisplatin and etoposide (BEP) chemotherapy regimens using immunohistochemistry. Forty male Wistar rats were divided into four groups of ten as; group 1 as untreated control; group 2 as BEP group which received the three cycles of 21 days' regimen each of 0.5¥ dose levels ofBEP (bleomycin 0.75 mg/kg, etoposide 7.5 mg/kg and cisplatin 1.5 mg/kg). Rats in the group 3 (MEL group) received 10 mg/kg/day melatonin once daily. Group 4 received the melatonin (30 min before the BEP injections) and BEP as in groups 2. Proliferating cell nuclear antigen (PCNA) staining was used to detect cell proliferation and caspase-3, caspase-9 and Caspase-8 were detected to investigate apoptosis. PCNA immunostaining in alveolar epithelium, alveolar macrophages and bronchus was weak to moderate in BEP group. However, diffuse and strong caspase immunoreactions for caspase-3, caspase 8- and caspase-9 were detected in the bronchioles epithelium, vascular endothelium, alveolar luminal macrophages in the BEP group. PCNA and caspase immunoreactivities in MEL and Mel + BEP groups were close to the control one. The surface are in the BEP group was significantly reduced as compared to the control one ((P0.05). It can be concluded that BEP regimen can affects negatively on lung tissue and melatonin inhibits lung tissue injuries during BEP chemotherapy.

El presente estudio investigó los posibles efectos protectores de la melatonina en los regímenes de quimioterapia con bleomicina, etopósido y cisplatino (BEP) mediante inmunohistoquímica. Cuarenta ratas Wistar macho se dividieron en cuatro grupos de diez: grupo 1, control sin tratar; grupo 2, quimioterapia con una dosis de 0,5x de BEP (0,75 mg/kg de bleomicina, 7,5 mg/ kg de etopósido y 1,5 mg/kg de cisplatino) con tres ciclos de 21 días cada uno. Las ratas del grupo 3 (grupo MEL) recibieron 10 mg/kg/día de melatonina una vez al día. El grupo 4 (Mel + BEP) recibió melatonina (30 minutos antes de las inyecciones de BEP) y BEP, como en los grupos 2. Se usó la tinción del antígeno nuclear de células en proliferación (PCNA) para detectar la proliferación celular y, caspasa- 3, caspasa-9 y caspasa-8 para investigar apoptosis. La inmunotinción de PCNA en el epitelio alveolar, los macrófagos alveolares y los bronquios varió de débil a moderada en el grupo BEP. Sin embargo, se detectaron inmunorreacciones difusas y fuertes para caspasa-3, caspasa 8- y caspasa-9 en el epitelio de los bronquiolos, endotelio vascular y macrófagos luminales alveolares. Las inmunorreactividades de PCNA y caspasa en los grupos MEL y Mel + BEP fueron similares a las del control. El área de superficie en el grupo BEP se redujo significativamente en comparación con el control (P0,05). Se puede concluir que la quimioterapia con BEP puede afectar negativamente al tejido pulmonar y la melatonina inhibe las lesiones durante la quimioterapia.

Effect of melatonin on peripheral nerve damage resulting from tibial defect in rats / Efecto de la melatonina sobre el daño de los nervios periféricos como resultado de un defecto tibial en ratas

SUMMARY: Peripheral nerve damage (PNI) can cause demyelination, axonal degeneration and loss of motor and sensory function. Melatonin with its antioxidative effect, has been reported to reduce scar formation in nerve injury, take a role in repair process by suppressing fibroblast proliferation in the damaged area. It was aimed to investigate the effect of melatonin in the repair of peripheral nerve damage and the relationship between S100 proteins and angiogenic regulation. Wistar albino rats were divided into 3 groups. In the Defect group, 6 mm tibial bone defect using a motorized drill was created and kept immobile for 28 days. In Defect + graft group, tibial bone defect with allograft treatment was applied and kept immobile for 28 days. In Defect + graft + Melatonin group, melatonin was administered to defect + allograft group. All rats were sacrified by decapitation, skin and tibia bone were removed then fixed with 10 % neutral buffered formalin and embedded in paraffin, sections were examined under light microscopy. In the Defect+Graft group, enlargement and occlusion of the vessels with degeneration of the epineural sheath, thickening of the endoneural sheath and mild hyperplasia of schwannocytus (Schwann cells) were remarkable. In the Defect+Graft+Melatonin group, the epineural sheath was tight and regular, the axonal structures were prominent in the endoneural area. Mild S100 expression was observed in Defect+Graft group in fibers of the endoneural region with a prominent expression in schwannocytus. In Defect+Graft+Melatonin group (10mg/kg), S100 expression was moderate in areas where schwannocytus proliferated and nerve-connective tissue sheaths were reconstructed. VEGF expression was moderate in endoneural, perineural and epineural connective tissue sheaths in the Defect+Graft+Melatonin group, with negative expression in blood vessel endothelial cells, but with a positive expression in schwannocytus. We conclude that with the application of melatonin; oxidative stress decreases, schwannocytus proliferation increases, having positive influence on nerve repair with the regulation of S100 signaling and angiogenetic structuring.

RESUMEN: El daño a los nervios periféricos puede causar desmielinización, degeneración axonal y pérdida de la función motora y sensorial. Se ha informado que la melatonina, con su efecto antioxidante, reduce la formación de cicatrices en lesiones nerviosas y desempeña un papel en el proceso de reparación al suprimir la proliferación de fibroblastos en el área dañada. El objetivo de este trabajo fue investigar el efecto de la melatonina en la reparación del daño de los nervios periféricos y la relación entre las proteínas S100 y la regulación angiogénica. Ratas albinas Wistar se dividieron en 3 grupos. En el grupo Defecto, se creó un defecto óseo tibial de 6 mm con un taladro motorizado y se mantuvo inmóvil durante 28 días. En el grupo Defecto + injerto, se aplicó tratamiento de defecto óseo tibial con aloinjerto y se mantuvo inmóvil durante 28 días. En el grupo Defecto + injerto + Melatonina, se administró melatonina al grupo defecto + aloinjerto. Todas las ratas fueron sacrificadas por decapitación, se extrajo la piel y el hueso de la tibia y luego se fijaron con formalina tamponada neutra al 10 % y se incluyeron en parafina, las secciones se examinaron bajo microscopía óptica. En el grupo Defecto+Injerto, fueron notables el agrandamiento y la oclusión de los vasos con degeneración de la vaina epineural, engrosamiento de la vaina endoneural e hiperplasia leve de los schwannocitos (neurolemnocitos). En el grupo Defecto+Injerto+Melatonina, la vaina epineural era estrecha y regular, las estructuras axonales eran prominentes en el área endoneural. Se observó expresión leve de S100 en el grupo Defecto+Injerto en fibras de la región endoneural con una expresión prominente en los schwannocitos. En el grupo Defecto+Injerto+Melatonina, la expresión de S100 fue moderada en áreas donde proliferaron los schwannocitos y se reconstruyeron las vainas de tejido conectivo nervioso. La expresión de VEGF fue moderada en vainas de tejido conectivo endoneural, perineural y epineural en el grupo Defecto+Injerto+Melatonina, con expresión negativa en células endoteliales de vasos sanguíneos, pero con expresión positiva en schwannocitos. Concluimos que con la aplicación de melatonina; disminuye el estrés oxidativo, aumenta la proliferación de schwannocitos, influyendo positivamente en la reparación nerviosa con la regulación de la señalización S100 y la estructuración angiogenética.

Use of melatonin as an inhibitor of apoptotic process for cryopreservation of zebrafish (Danio rerio) embryos / Uso da melatonina como inibidor do processo apoptotico para a criopreservação de embriões de zebrafish (Danio rerio)

This study investigated the use of melatonin to arrest the effects of apoptosis in vitrified zebrafish (D. rerio) embryos. Dechorionated embryos at 22-24 somite-stage were divided (n = 60/treatment) into a non-vitrified (Control Group, 0 M melatonin) and vitrified treatments with 0 M (T1), 1 µM (T2) and 1 mM of melatonin (T3). For vitrified treatments, a solution methanol/propylene glycol based was used and the embryos stored in -196 °C for a week. After thaw, survival rate, scanning electron microscopy, expression of anti (bcl-2) and pro-apoptotic (bax/caspase-3) genes, reactive oxygen species (ROS) formation and DNA fragmentation analyses were performed. No live embryos were obtained from vitrified treatments, observing a rapid degeneration immediately after thawing, with the vitelline layer rupture and leakage of its content, followed by breakdown of epithelial cells and melanisation of the tissue. Regarding the apoptotic process, T3 had the highest relative gene expression, for the three genes (P 0.05). The inclusion of 1 µM of melatonin in the vitrifying solution, countered the effects of apoptotic process in post-thaw embryos, suggesting its utility in cryopreserving fish embryos.

Este estudo investigou o uso da melatonina para conter os efeitos da apoptose em embriões vitrificados de zebrafish (D. rerio). Embriões descorionados no estágio de 22-24 somitos foram divididos (n = 60 / tratamento) em tratamento não vitrificado (Grupo Controle, melatonina 0 M) e tratamentos vitrificados com 0 M (T1), 1 µM (T2) e 1 mM de melatonina (T3). Para os tratamentos vitrificados, utilizou-se uma solução à base de metanol/propilenoglicol e os embriões foram armazenados em -196 °C por uma semana. Após o descongelamento, foram realizadas análises de taxa de sobrevivência, microscopia eletrônica de varredura, expressão dos genes anti (bcl-2) e pró-apoptóticos (bax/caspase-3), formação de espécies reativas de oxigênio (EROS) e análises de fragmentação de DNA. Não foram obtidos embriões vivos a partir dos tratamentos vitrificados, observando uma rápida degeneração imediatamente após o descongelamento, com ruptura da camada vitelina e vazamento de seu conteúdo, seguida de quebra das células epiteliais e melanização do tecido. Em relação ao processo apoptótico. T3 apresentou expressão gênica relativa alta para os três genes (P 0,05). A inclusão de 1 µM de melatonina na solução de vitrificação, contrariou os efeitos do processo apoptótico em embriões pós-descongelamento, sugerindo sua utilidade na criopreservação de embriões de peixes.

Effects of melatonin against thioacetamide-induced testicular toxicity in rats / Efectos de la melatonina contra la toxicidad testicular inducida por tioacetamida en ratas

SUMMARY: This study aimed to investigate the changes in testis tissue of thioacetamide-induced rats and the effect of melatonin on these changes. Thirty-five male Wistar Albino rats were divided into five groups. Group I; Control (n=7), Group II; Melatonin (Mel) (10 mg/kg) a single dose (i.p)(n=7), Group III; Thioacetamide (TAA) (300 mg/kg) (i.p) 2 times with 24 hour intervals (n=7), Group IV; TAA (300 mg/kg) was administered at 24-hour intervals, afterwards of 10 mg/kg single dose of Mel (n=7), Group V; Mel was administered 10 mg/kg a single dose 24 hours before the administration of TAA (n=7). Testis was evaluated histologically, immunohistochemically (Heat Shock Proteins (HSP) 70 and 90), blood serum testosterone, total antioxidant status(TAS) and total oxidant status(TOS) in tissue. The tissue sections of Group III decreased seminiferous tubule diameters, and germinal epithelium spills were observed. HSP70 and HSP90 expressions were increased. There wasn't a statistically significant change in testosterone levels among the groups. While TAS levels decreased in Group III compared to control, TOS levels didn't change. HSP70 and HSP90 decreased in groups with Mel-treated. Mel was found to have both protective and therapeutic effects. According to our results, the therapeutic effect of Mel in thioacetamide-induced acute testicular injury is greater than its protective effect.

RESUMEN: Este estudio tuvo como objetivo investigar los cambios en el tejido testicular de ratas inducidas por tioacetamida y el efecto de la melatonina en estos cambios. Treinta y cinco ratas macho Wistar Albino se dividieron en cinco grupos. Grupo I; Control (n = 7), Grupo II; Melatonina (Mel) (10 mg / kg) una dosis única (i.p) (n = 7), Grupo III; Tioacetamida (TAA) (300 mg / kg) (i.p) 2 veces con intervalos de 24 horas (n = 7), Grupo IV; TAA (300 mg / kg) se administró a intervalos de 24 horas, luego de una dosis única de 10 mg / kg de Mel (n = 7), Grupo V; Mel recibió 10 mg / kg de una dosis única 24 horas antes de la administración de TAA (n = 7). Los testículos se evaluaron histológicamente, inmunohistoquímicamente (proteínas de choque térmico (PCT) 70 y 90), testosterona en suero sanguíneo, estado antioxidante total (EAT) y estado oxidante total (EOT) en el tejido. En secciones de tejido del Grupo III se observó disminución de los diámetros de los túbulos seminíferos y derrames en el epitelio germinal. Se aumentaron las expresiones HSP70 y HSP90. No hubo un cambio estadísticamente significativo en los niveles de testosterona entre los grupos. Mientras que los niveles de EAT disminuyeron en el Grupo III en comparación con el control, los niveles de EOT no cambiaron. HSP70 y HSP90 disminuyeron en los grupos tratados con Mel. Se descubrió que Mel tenía efectos protectores y terapéuticos. Según nuestros resultados, el efecto terapéutico de Mel en la lesión testicular aguda inducida por tioacetamida es mayor que su efecto protector.

Variable beige adipocyte morphology in obese rats by different times of melatonin administration / Variación de la morfología del adipocito beige en ratas obesas según los diferentes tiempos de administración de melatonina

This study aimed to evaluate changes in beige adipocytes at different times of melatonin administration, in the morning (ZT01) or in the evening (ZT11), at 30 mg/kg daily by gavage for 7 weeks or continuously with drinking water in the term of high-calorie diet-induced obesity (HCD). Melatonin received at ZT11 or with drinking water resulted in an increased area of the browning zone in the subcutaneous white adipose tissue (sWAT), even in rats with HCD (compared with Control or HCD, respectively). The beige adipocyte and lipid droplet area after melatonin use were reduced compared to those with HCD and Control, in all administration modes (group ZT01 showed smaller changes compared to ZT11 or with drinking water groups). The fibrosis level decreased and significantly differed in HCD ZT01, HCD ZT11, and HCD water compared to that in HCD; moreover, the lowest value determined in HCD water, reached the control parameters. Furthermore, the IL-1b and IL-8 level was decreased in the HCD groups under melatonin treatment at ZT11 or with drinking water compared to that in HCD. The obtained results suggest that melatonin promotes sWAT browning in rats with diet-induced obesity and influences morphological signs of normal rats depending on the time of administration. Different functional activity of beige adipocytes was observed after melatonin was used depending on the time of administration, resulting in heat production and lipolysis (the relative mass of visceral fat was likewise diminished). More rapid browning was observed when melatonin treatment was performed at 1 h before lights-off (ZT11) or continuously via drinking water. Melatonin acted on beige adipocytes of obese rats through changing some parameters such as the area of adipocytes and lipid drops, the number of lipid drops, the relative area browning of sWAT, and the level of tissue fibrosis.

Este estudio tuvo como objetivo evaluar los cambios en los adipocitos beige en diferentes momentos de la administración de melatonina, en la mañana (ZT01) o por la noche (ZT11). Se administraron 30 mg/kg diariamente por sonda durante 7 semanas o continuamente con agua potable durante el periodo de obesidad inducida por una dieta alta en calorías (HCD). La melatonina recibida en ZT11 o con agua potable resultó en un aumento de área dorada en tejido adiposo blanco subcutáneo (sWAT), incluso en ratas con HCD (en comparación con Control o HCD, respectivamente). El área de gotas de lípidos y adipocitos de color beige después del uso de melatonina se redujo en comparación con aquellos con HCD y Control, en todos los modos de administración (el grupo ZT01 mostró cambios más pequeños en comparación con ZT11 o con grupos de agua potable). El nivel de fibrosis disminuyó y difirió significativamente en HCD ZT01, HCD ZT11 y agua HCD, en comparación con el HCD; además, el valor más bajo determinado en agua HCD alcanzó los parámetros de control. Además, el nivel de IL-1b e IL-8 disminuyó en los grupos HCD bajo tratamiento con melatonina en ZT11 o con agua potable en comparación con el de HCD. Los resultados obtenidos sugieren que la melatonina promueve el dorado sWAT en ratas con obesidad inducida por la dieta e influye en los signos morfológicos de las ratas normales dependiendo del momento de la administración. Se observó una actividad funcional diferente de los adipocitos de color beige después de usar melatonina dependiendo del tiempo de administración, dando como resultado la producción de calor y lipólisis (la masa relativa de grasa visceral también disminuyó). Se observó un ennegrecimiento más rápido cuando el tratamiento con melatonina se realizó 1 h antes de apagar las luces (ZT11) o de forma continua en grupos de agua potable. La melatonina actuó en los adipocitos beige de ratas obesas al cambiar algunos parámetros, como el área de adipocitos y gotas de lípidos, el número de gotas de lípidos, el área relativa de ennegrecimiento de sWAT y el nivel de fibrosis tisular.

Melatonin and organ transplantation: what is the relationship?

SUMMARY Melatonin has anti-inflammatory and antioxidant properties that can influence tissue growth and apoptosis. This aspect may influence the success of organ transplantation. OBJECTIVE To evaluate the relationship between melatonin and organ transplantation. METHODS A systematic review was performed in PubMed databases using the search terms: "melatonin physiology" or "melatonin therapy" and "transplant pharmacology" or "transplant physiology" or "transplant therapy" or "Transplant therapy". Experiments on the organs of the reproductive system were not included. After analysis, five articles were selected after reading the title and abstract of 50 manuscripts. The works were divided into two aspects: a) analysis of the influence of the organ transplantation procedure on melatonin production; b) action of melatonin on organ transplantation. RESULTS The cardiac transplantation surgical procedure, immunosuppression, and graft did not influence melatonin secretion in rodents, but there was a significant reduction of melatonin in the renal transplantation procedure in patients with renal insufficiency. Melatonin administration in experimental models decreased rejection and improved transplant success. CONCLUSION Studies show that melatonin can reduce organ and species dependence, and the use of melatonin decreases graft rejection.

RESUMO A melatonina tem propriedades anti-inflamatórias e antioxidantes que podem influenciar o crescimento e a apoptose dos tecidos. Esse aspecto pode influenciar o sucesso do transplante de órgãos. OBJETIVO Avaliar a relação entre a melatonina e o transplante de órgãos. MÉTODO A revisão sistemática foi realizada nas bases de dados do PubMed, usando os termos de pesquisa: "fisiologia da melatonina" ou "terapêutica da melatonina" e "farmacologia do transplante" ou "fisiologia do transplante" ou "terapêutica do transplante" ou "terapia do transplante". Não foram incluídos os experimentos sobre os órgãos do sistema reprodutivo. Após análise, cinco artigos foram selecionados após a leitura do título e do resumo de 50 manuscritos. Os trabalhos foram divididos em duas vertentes: a) análise da influência do procedimento de transplante de órgão na produção de melatonina; b) ação da melatonina sobre o transplante de órgãos. RESULTADOS O procedimento cirúrgico do transplante cardíaco, a imunossupressão e o enxerto não influenciaram a secreção de melatonina em roedores, mas houve redução significante da melatonina nos casos do procedimento de transplante renal em pacientes com insuficiência renal. A ministração de melatonina em modelos experimentais diminuiu a rejeição e melhorou o sucesso de transplante. CONCLUSÃO Os estudos mostram que a melatonina pode reduzir a dependência da espécie e do órgão e que o emprego da melatonina diminui a rejeição do órgão.

Protective effect of combined melatonin and alpha-tocopherol administration in spinal cord ischemia-reperfusion injury in rat / Efecto protector de la administración combinada de melatonina y alfa-tocoferol en la lesión por isquemia-reperfusión de la médula espinal en ratas

Oxidative stress and inflammation are the key players in the development of motor dysfunction post-spinal cord ischemic reperfusion injury (SC-IRI). This study investigated the protective effect of concomitant pre-administration of melatonin and alpha-tocopherol on the early complications (after 48 hours) of spinal cord IRI injury in rats. Melatonin or α-tocopherol were preadministered either individually or in combination for 2 weeks, then rats were exposed SC-IRI. Neurological examinations of the hind limbs and various biochemical markers of oxidative stress and inflammation in the SC tissue were assessed. Solely pre-administration of either melanin or α-tocopherol significantly but partially improved motor and sensory function of the hind limbs mediated by partial decreases in SC levels of MDA, AOPP and PGE2 levels and activities of SOD, partial significant decreases in plasma levels of total nitrate/nitrite and significant increases in AC activity of GSH-Px. However, combination therapy of both drugs resulted in the maximum improvements in all neurological assessments tested and biochemical endpoints. In conclusion, by their synergistic antioxidant and antiinflammatory actions, the combination therapy of melatonin and α-tocopherol alleviates SC-IRI induced paraplegia.

El estrés oxidativo y la inflamación son claves en el desarrollo de la disfunción motora posterior a lesión isquémica de la médula espinal (SC-IRI). Este estudio investigó acerca del efecto protector de la administración previa concomitante de la melatonina y alfa-tocoferol en las complicaciones tempranas (después de 48 horas) de la lesión de IRI de la médula espinal en ratas. La melatonina o el α-tocoferol se administraron individualmente o en combinación durante 2 semanas, luego las ratas fueron expuestas a SC-IRI. Se evaluaron los exámenes neurológicos de las miembros pélvicos y diversos marcadores bioquímicos de estrés oxidativo e inflamación en el tejido subcutáneo. Solo la administración previa de melatonina o α-tocoferol mejoró parcial y significativamente la función motora y sensorial de los miembros pélvicos mediadas por disminuciones parciales en los niveles de SC de los niveles de MDA, AOPP y PGE2 y las actividades de la SOD, disminuciones significativas parciales en los niveles plasmáticos del total nitrato / nitrito y aumentos significativos en la actividad de AC de GSH-Px. Sin embargo, se observaron los mejores resultados durante la combinación de ambos fármacos en todas las evaluaciones neurológicas y en los puntos finales bioquímicos. En conclusión, debido a sus acciones antioxidantes y antiinflamatorias sinérgicas, la terapia de melatonina y α-tocoferol alivia la paraplejía inducida por SC-IRI.

Effect of melatonin on the daytime sleepiness side-effect of gabapentin in adults patients with neuropathic pain / Efeito da melatonina sobre o efeito colateral de sonolência diurna da gabapentina em pacientes adultos com dor neuropática

Abstract Background and objectives: Gabapentin is an antiepileptic drug. Widely used for the management of neuropathic pain. Although it is known to be well tolerated, somnolence and dizziness are the most frequent adverse effects. In this study, we aimed to evaluate the effect of melatonin on daytime sleepiness side effect of gabapentin, sleep quality and pain intensity of patients with neuropathic pain. Methods: Patients suffering from "neuropathic pain" and planed to receive gabapentin therapy were randomly divided into two groups. Group 1 received melatonin 3 mg and gabapentin 900 mg orally, group 2 received matching placebo capsule and gabapentin 900 mg. The Epworth Sleepiness Scale, the Pittsburgh sleep quality index for assessment of sleep quality and Verbal Rating Scale were completed at the 0th, 10th and 30th days of treatment. Additive analgesic drug requirements were recorded. Results: Eighty patients were enrolled to the study; age, gender, ratio of additive analgesic consumption, baseline Epworth Sleepiness Scale, Pittsburg Sleep Quality index and Verbal Rating Scale scores were similar between the groups. Epworth Sleepiness Scale scores, Pittsburgh sleep quality index scores and Verbal Rating Scale scores in Group 1 were significantly lower than group 2 at the 10th day of treatment (p = 0.002, p = 0.003, p = 0.002 respectively). At the 30th day of treatment, Epworth Sleepiness Scale scores and Verbal Rating Scale scores were significantly lower in Group 1 (p = 0.002, p = 0.008 respectively). However, Pittsburgh sleep quality index scores did not significantly differ between the groups (p = 0.0566). Conclusions: Melatonin supplementation rapidly and significantly improved daytime sleepiness side-effect of gabapentin, however sleep quality of the patients with neuropathic pain was similar between groups.

Resumo Justificativa e objetivos: Gabapentina é um agente antiepiléptico, amplamente utilizado para o tratamento da dor neuropática. Embora conhecida por ser bem-tolerada, sonolência e tontura são os seus efeitos adversos mais frequentes. Neste estudo, nosso objetivo foi avaliar o efeito da melatonina sobre o efeito colateral de sonolência diurna da gabapentina, a qualidade do sono e a intensidade da dor em pacientes com dor neuropática. Métodos: Os pacientes que sofriam de "dor neuropática" e com prescrição para receber terapia com gabapentina foram divididos aleatoriamente em dois grupos. O Grupo 1 recebeu 3 mg de melatonina e 900 mg de gabapentina por via oral, o Grupo 2 recebeu uma cápsula de placebo correspondente e 900 mg de gabapentina. A escala de sonolência de Epworth (ESS), o índice de qualidade do sono de Pittsburgh para avaliação da qualidade do sono (PSQI) e a escala de avaliação verbal (VRS) foram aplicados nos dias 0, 10 e 30 de tratamento. A necessidade de medicamentos analgésicos adicionais foi registrada. Resultados: Oitenta pacientes foram incluídos no estudo; idade, sexo, quantidade de analgésico adicional consumida e os escores basais de ESS, PSQI e VRS foram semelhantes entre os grupos. Os escores ESS, PSQI e VRS do Grupo 1 foram significativamente menores que os do Grupo 2 no décimo dia de tratamento (p = 0,002, p = 0,003, p = 0,002, respectivamente). No trigésimo dia de tratamento, os escores ESS e VRS foram significativamente menores no Grupo 1 (p = 0,002, p = 0,008, respectivamente). No entanto, os escores PSQI não diferiram significativamente entre os grupos (p = 0,0566). Conclusões: A suplementação de melatonina melhorou de forma rápida e significativa o efeito colateral de sonolência diurna da gabapentina, mas a qualidade do sono dos pacientes com dor neuropática foi semelhante entre os grupos.

Acute melatonin administration enhances aerobic tolerance: an analysis of biochemical and hematological parameters

Aims: This study is aimed at testing the acute melatonin administration (oral; 6 mg) on aerobic tolerance at cycloergometer and analyzing the consequences on biochemical and hematological parameters. Methods: The maximal aerobic capacity intensity (iMAC) at cycloergometer of eleven male healthy men (24.18±3.92 years-old; 87.07±12.48 kg; 1.82±0.05 m; 26.18±3.63 kg/m2; and 16.28±5.77 % of fat) was individually determined and used to perform a time to exhaustion (tlim) trial of 30 minutes after melatonin or placebo administration. We observed 48-72h interval between tests, performed in a double-blind experiment design. In order to determine hematological and biochemical parameters we collected venous blood samples before and after tlim. Statistical significance was set at 5%. Results The intensity and the lactatemia corresponding to the maximal aerobic capacity were 120.88±18.78 W and 3.32±1.03 mmol.L-1, respectively. The tlim with placebo (33.94±15.26 min, confidence interval = 24.92 - 42.95) was significantly lower than the tlim with melatonin (41.94±17.22 min; CI = 31.76 - 52.12; p = 0.03; 19.06%; effect size = 0.49). All of the 21 analyzed blood physiological variables resulted in no significant variation after tlim when placebo was compared to melatonin, except for total sera cholesterol (lower after exercise with melatonin). Conclusion: Acute melatonin administration enhanced aerobic tolerance at iMAC in 19% at cycloergometer; however, the biochemical and hematological variables assessed were not significantly modulated.(AU)

Systemic melatonin application increases bone formation in mandibular distraction osteogenesis

Abstract This study aimed to investigate the effects of different doses of systemic melatonin application on new bone formation during mandibular distraction osteogenesis (DO) in rats. Mandibular DO was performed on 30 adult female Sprague-Dawley rats, which were randomly divided into three groups: control group (CNT), melatonin dose 1 (MLT-D1), and melatonin dose 2 (MLT-D2). A five-day latent waiting period and a ten-day distraction phase followed the surgery. After the surgery, rats from the MLT-D1 and MLT-D2 groups received 25 and 50 mg/kg melatonin, respectively, at 7, 14, 21, 28, and 35 days. The animals were euthanised 28 days after distraction, i.e. at 43 days after surgery. Histological and histomorphometric analyses revealed that the distracted bone area was completely filled with new bone formation in all three groups. The MLT-D2 group exhibited the most new bone formation, followed by MLT-D1 and CNT. The melatonin groups had more osteoclasts than the CNT (p < 0.05). The number of osteoblasts was higher in the melatonin groups than in the CNT group, and the MLT-D2 had more osteoclasts than the MLT-D1 group (p < 0.05). Finally, the osteopontin (OPN) and vascular endothelial growth factor (VEGF) levels were higher in the melatonin groups than in the CNT group, and the MLT-D2 had higher OPN and VEGF levels than the MLT-D1 (p < 0.05). This study suggests that systemic melatonin application could increase new bone formation in DO.

The effect of melatonin and vitamin C treatment on the experimentally induced tympanosclerosis: study in rats / Efeito do tratamento com melatonina e vitamina C na timpanoesclerose induzida experimentalmente: estudo em ratos

Abstract Introduction: The ethiopathogenesis of tympanosclerosis has not been completely under- stood yet. Recent studies have shown that free oxygen radicals are important in the formation of tympanosclerosis. Melatonin and Vitamin C are known to be a powerful antioxidant, interacts directly with Reactive Oxygen Species and controls free radical-mediated tissue damage. Objective: To demonstrate the possible preventative effects of melatonin and Vitamin C on tympanosclerosis in rats by using histopathology and determination of total antioxidant status total antioxidant status. Methods: Standard myringotomy and standard injury were performed in the middle ear of 24 rats. The animals were divided into three groups: Group 1 received melatonin, Group 2 received vitamin C, and Group 3 received saline solution. Results: The mean values of total antioxidant status were similar in the all study groups before the treatment period. The mean values of total antioxidant status were significantly higher in the melatonin and vitamin C groups compared to control group but vitamin C with melatonin groups were similar after the treatment period (p < 0.001). Minimum and maximum wall thicknesses were lower in the melatonin and vitamin C groups compared to the control group but the differences were insignificant. Conclusion: Melatonin increases total antioxidant status level and might have some effect on tympanosclerosis that develops after myringotomy.

Resumo Introdução: A etiopatogênese da timpanoesclerose (TE) não foi ainda totalmente esclarecida. Estudos recentes têm demonstrado que os radicais livres de oxigênio são importantes na formação de TE. Melatonina e vitamina C são conhecidas por serem poderosos antioxidantes, interagir diretamente com espécies reativas de oxigênio (ROS) e controlar danos em tecidos mediados por radicais livres. Objetivo: Demonstrar os possíveis efeitos preventivos da melatonina e da vitamina C na TE em ratos com histopatologia e determinação da capacidade antioxidante total (CAT). Método: Miringotomias padronizadas foram feitas na orelha média de 24 ratos. Os animais foram divididos em três grupos: o Grupo 1 recebeu melatonina, o Grupo 2 vitamina C e o grupo 3 solução salina. Resultados: Os valores médios de CAT foram semelhantes em todos os grupos de estudo antes do período de tratamento. Os valores médios de CAT foram significativamente maiores nos grupos que receberam melatonina e vitamina C em comparação com o grupo de controle, mas os grupos vitamina C e melatonina foram semelhantes após o período de tratamento (p < 0,001). As espessuras mínimas e máximas de parede foram menores nos grupos melatonina e vitamina C, em comparação com o grupo controle, mas as diferenças não foram significativas. Conclusão: A melatonina aumenta os níveis de CAT e pode ter algum efeito sobre a TE que se desenvolve após a miringotomia.

Efecto de la administración prenatal de melatonina en pulmones de neonatos de oveja crónicamente hipóxicos / Effect of prenatal administration of melatonin on lungs of chronic hypoxic sheep neonates

Introducción: Las patologías que podrían motivar el ingreso a una Sala de Reanimación (SR) son múltiples, y asimismo, presentarse en cualquier momento, independientemente del sexo y la edad. A pesar de esta versatilidad, no existen investigaciones que describan la realidad chilena y la literatura extranjera es escasa. En consecuencia, nuestro estudio buscó caracterizar clínico-demográficamente a los pacientes ingresados a SR del Hospital San Juan de Dios de Los Andes, Chile. Materiales y métodos: Estudio de corte transversal. Se trabajó con base de datos anonimizada. El tamaño muestral calculado fue de al menos 1014 sujetos (intervalo de confianza de 95%, precisión de 3%). Se incluyeron los ingresos entre enero de 2013 y junio de 2016, obteniendo una muestra de 1018 pacientes. Variables estudiadas: sexo, edad, diagnóstico general, diagnóstico específico, mes y horario. Se trabajó con Microsoft Excel® utilizando estadística descriptiva. Aprobado por comité éticocientífico. Resultados: 58,1% (n=593) hombres; 42,5% (n=434) mayores de 64 años. Diagnósticos generales más frecuentes: cardiovascular (50,3%) (n=512), neurológico (16,3%) (n=166) y traumático (11,7%) (n=119). Diagnósticos específicos más frecuentes: taquiarritmia (15,9%) (n=162) e infarto miocárdico (12,6%) (n=128). La mayor cantidad de ingresos se registró en enero, febrero y junio (promedio 28 ingresos), y entre las 20 y 00 hrs (22,8%) (n=232). Discusión: Existe un amplio predominio de las enfermedades cardiovasculares.La distribución por mes, sexo y edad parece estar supeditada al comportamiento de dicho grupo; no así la distribución por horarios, ya que las enfermedades cardiovasculares suelen presentarse matinalmente. En general, nuestros resultados coinciden con la literatura extranjera disponible

Introduction: Neonatal pulmonary hypertension (NPHT) caused by chronic hypobaric hypoxia during gestation is associated with oxidative stress and currently lacks of an effective treatment. The aim of this study was to evaluate the effects of melatonin administrated on pregnant sheep on endothelium-dependent vascular reactivity and expression of eNOS, COX-1 and COX-2 on the lungs of lambs gestated and born under chronic hypobaric hypoxia. Material and method: Ten pregnant ewes under chronic hypoxia of highlands (3600 masl) were divided in two groups: 1. Control group (CN), treated with vehicle (5 ml/d ethanol 1, 4%), and 2. Melatonin group (MM), treated with melatonin during gestation (10 mg/d in 5 ml ethanol 1, 4%), during the last third of gestation. Results: Ewes gave birth spontaneously and without assistance, and we obtained lung tissue from 12 days old lambs to determine endothelial vascular reactivity by wire myography. In addition, eNOS, COX-1 and COX-2 RNA and protein expression were measured through RT-PCR and Western Blot, respectively. Discussion: The endothelium dependent vasodilation response was significantly enhanced in MM. Further, MM showed a significant increase in eNOS, COX-1 and COX-2 protein levels, relative to CN group. In conclusion, prenatal melatonin induces endothelium dependent vasodilation mechanisms and positively modulates eNOS-NO and prostanoids pathways, which may favour a treatment for NPHT caused by chronic hypoxia at high-altitude

Adição da proteína específica do oviduto de porcas (pOSP) e da melatonina em meios de maturação e o efeito na clivagem in vitro de embriões suínos / Addition of the oviduct specific protein of porcine (pOSP) and melatonin in maturation media and their effect on the in vitro production of pig embryos

No presente estudo, utilizou-se a melatonina e a proteína específica do oviduto (pOSP) nos meios de maturação in vitro. Foram avaliadas a expansão do complexo cumulus-ovócito (CCOs), as concentrações intracelulares de espécies reativas de oxigênio (ROS) e o desenvolvimento embrionário nos diferentes grupos (C = controle; T1 = somente com melatonina; T2 = com melatonina e pOSP e T3 somente com pOSP). No tocante à expansão do CCOs, houve diferença (P<0,05) dos valores obtidos no grupo C em relação aos valores médios dos grupos T1, T2 e T3, porém não houve diferença entre os valores obtidos nos tratamentos (P>0,05). Na dosagem de ROS, não houve diferença entre os valores médios obtidos no grupo C (26,4±10,9) e o valor verificado no grupo T1 (23,4±7,8), porém no grupo T2 (21,3±9,7) o valor médio mostrou-se satisfatório em relação ao valor do grupo C. No entanto, o valor médio do grupo T3 (16,6±10,5) foi o que demonstrou resultado mais satisfatório quando comparado aos demais grupos (P<0,05). A produção de embriões foi avaliada por meio da taxa de clivagem. Não houve diferença (P >0,05) entre os valores obtidos entre o grupo C (48,9 %) e os valores verificados nos grupos T1 (51,5 %), T2 (50 %), T3 (57,7 %), nem destes entre si. Este estudo permitiu concluir que a proteína específica do oviduto recombinante e a melatonina foram eficientes em melhorar a expansão dos CCOs. Além disso, as células tratadas com pOSP mostraram-se com menor quantidade de ROS, podendo a pOSP ser considerada um antioxidante proteico.(AU)

The present study used melatonin and recombinant oviduct specific protein (pOSP) in in vitro maturation medium (IVM). The expansion of the cumulus-oocyte complexes (COCs), the intracellular concentrations of reactive oxygen species (ROS) and embryo development of the different groups were evaluated (C = control; T1 = melatonin; T2 = melatonin and pOSP and T3 = pOSP). Regarding the COCs expansion, the groups T1, T2 and T3 showed satisfactory results compared with group C (P<0.05), but there was no difference between treatments (P>0.05). In the ROS dosage, there was no difference between the mean values obtained in group C (26.4 ± 10.9) and group 1 (23.4 ± 7.8). However, in group 2 (21.3 ± 9.7), the average value was found to be satisfactory in relation group C. Despite that, the average value of treatment 3 (16.6 ± 10.5) was the most satisfactory result found compared to the other groups (P<0.05). The production of embryos was evaluated by cleavage rate, there was no difference between the values obtained in group C and the values recorded in groups T1 (51.5 %), T2 (50 %), T3 (57.7 %), and among them. This study showed that the pOSP and the melatonin were effective in the improvement of the expansion of COCs cells. In addition, the cells that were treated with pOSP presented a lower amount of ROS, allowing the pOSP to be considered a proteic antioxidant.(AU)

Efeito de diferentes concentrações de melatonina em espermatozoides de carneiros sobre estresse oxidativo após criopreservação / Effect of different concentrations of melatonin to ram spermatozoa on oxidative stress after cryopreservation

Objetivou-se avaliar o efeito da adição de diferentes concentrações de melatonina no sêmen diluído de carneiros após criopreservação. Foram coletados 10 ejaculados de três carneiros adultos (n=30), por meio de vagina artificial para ovinos. Os ejaculados coletados foram diluídos em Tris-Gema de ovo, para a concentração final de 200x106 sptz/mL, mantidos em banho maria a 32°C, e a melatonina adicionada conforme os tratamentos: Controle; 100pM; 100nM; 100µM e 1mM de melatonina. Então, as amostras foram resfriadas em câmara fria a 5°C por duas horas, envasadas em palhetas de 0,5 mL e lacradas. Logo após, foram acondicionadas sob vapores do nitrogênio liquido, por 15 minutos, a 8cm da lâmina líquida e congeladas com nitrogênio líquido. As amostras foram analisadas quanto à motilidade espermática, integridade da membrana plasmática, membrana acrossomal, atividade mitocondrial, quantificação do estresse oxidativo e a capacidade de ligação. As variáveis foram submetidas à análise de variância e as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. A motilidade total e progressiva dos espermatozoides descongelados foi maior nas amostras tratadas com 100pM de melatonina (62,99 e 45,07% respectivamente; P<0,05) quando comparado aos demais tratamentos. A adição das diferentes concentrações de melatonina no sêmen diluído, com exceção da concentração de 1 mM, apresentou maior percentual de células com membrana plasmática íntegra, quando comparadas com o controle (P<0,05). O percentual de espermatozoides com integridade da membrana do acrossoma foi maior no sêmen tratado com 100 pM de melatonina (P<0,05) do que nos demais tratamentos. A alta atividade mitocondrial foi maior nos espermatozoides tratados com 100 pM de melatonina (69,30%; P<0,05). A adição de 100 nM de melatonina reduziu a quantidade de TBARS após a criopreservação (2,84; P<0,05) quando comparado aos demais tratamentos. Após o descongelamento, o número de espermatozoides que se ligaram à membrana perivitelina foi maior nos tratados com 100 pM de melatonina (155,73; P<0,05). Portanto, a adição de melatonina no sêmen diluído pode ser útil para aperfeiçoar a criopreservação do sêmen de ovinos, melhorando as taxas de fertilização por meio da inseminação artificial.(AU)

The aim was to evaluate the effect of adding different concentrations of melatonin in ram semen diluted after cryopreservation. Ten ejaculates were collected0 from three adult ram (n=30) by means of artificial vagina for sheep. The collected samples were diluted in Tris-egg yolk, to a final concentration 200x106 sptz/mL kept in water bath at 32°C, and melatonin added as treatments: control; 100pM; 100nM; 100µM and 1mM melatonin. Then, the samples were cooled in a cold chamber at 5°C for two hours, in straws of 0.5mL and sealed. They were stored under the liquid nitrogen vapor for 15 minutes to 8cm of liquid blade and frozen with liquid nitrogen. Samples were analyzed for sperm motility, membrane integrity, acrosomal membrane, mitochondrial activity, oxidative stress and quantification of the binding capacity. The variables were subjected to analysis of variance and the means were compared by Tukey test at 5% probability. The total and progressive motility of thawed sperm were higher in samples treated with 100pM melatonin (62.99 and 45.07%, respectively; P<0.05) when compared to other treatments. The addition of different concentrations of melatonin in semen diluted with the exception of 1mM concentration, a higher percentage of cells with intact plasma membrane, as compared with the control (P<0.05). The percentage of sperm with acrosome membrane integrity was higher in the semen with 100pM melatonin (P<0.05) than the other treatments. The high mitochondrial activity was higher in spermatozoa treated with 100pM melatonin (69.30%; P<0.05). Addition of 100nM melatonin reduced the amount of TBARS after cryopreservation (2.84, P<0.05) when compared with the other treatments. After thawing, the number of sperm which bind to the perivitelline membrane was higher in the melatonin treated with 100pM (155,73; P<0.05). Therefore, melatonin addition the semen diluted can be useful to enhance the cryopreservation of sheep semen, improving fertilization rates through artificial insemination.(AU)

Effects of melatonin on tibia bone defects in rats / Efectos de la melatonina sobre defectos óseos en la tibia de ratas

The aim of this study was to evaluate the effects of melatonin healing in a tibial bone defect model in rats by means of histopathological and immunohistochemistry analysis. Twenty one male Wistar albino rats were used in this study. In each animal, bone defects (6 mm length ) were created in the tibias. The animals were divided into three groups. In group 1 control group (rats which tibial defects). Group 2 melatonin (10 mg/kg) + 14 days in the tibial defect group) was administered intraperitoneally to rats. Group 3 melatonin (10 mg/kg) + 28 days in the tibial defect group) was administered intraperitoneally to rats. Histopathological analysis of samples was performed to evaluate the process of osteoblastic activity, matrix formation, trabecular bone formation and myeloid tissue in bone defects. Immunohistochemical and immunoblot analysis demonstrated non-collagenous proteins (osteopontin and osteonectin) differences in tibial bone defects. The expression of osteopontin on tibia was increased by 14 days melatonin treatment. The expression of osteonectin on tibia was dramatically increased by 14 days melatonin treatment.

El objetivo fue evaluar por medio de análisis histopatológico e inmunohistoquímico los efectos cicatrizantes de la melatonina en un modelo de defecto óseo tibial en ratas. Se utilizaron 21 ratas albinas Wistar macho. En cada animal, se crearon defectos óseos en las tibias de 6 mm de longitud. Los animales se dividieron en tres grupos. El Grupo 1 correspondió al grupo control (defectos tibiales sin tratamiento). Al Grupo 2 se administró melatonina por vía intraperitoneal (10 mg/kg) 14 días posteriores al defecto tibial. Al Grupo 3 se administró melatonina por vía intraperitoneal (10 mg/kg) 28 días posteriores al defecto tibial. Se realizó un análisis histopatológico para evaluar los procesos de actividad osteoblástica, formación de matriz, formación de hueso trabecular y tejido mieloide en los defectos óseos. Los análisis inmunohistoquímicos y de inmunotransferencia mostraron diferencias de proteínas no colágenas (osteopontina y osteonectina). La expresión de osteopontina en defectos óseos tibiales se incrementó en el Grupo 2. La expresión de osteonectina en la tibia se incrementó fuertemente bajo el tratamiento con melatonina por 14 días.

The effects of supplemental melatonin administration on the healing of bone defects in streptozotocin-induced diabetic rats

ABSTRACT Diabetes mellitus (DM) causes an increased production of free radicals that can impair bone healing. Melatonin is a hormone secreted mainly by the pineal gland, which participates in the neutralization process of free radicals. Objective The aim of this study was to investigate histologic and biochemical effects of supplemental melatonin administration on bone healing and antioxidant defense mechanism in diabetic rats. Material and Methods Eighty-six Sprague-Dawley male rats were used in this study. Diabetes mellitus was induced by intraperitoneal (i.p.) administration of 65 mg/kg streptozotocin (STZ). Surgical bone defects were prepared in the tibia of each animal. Diabetic animals and those in control groups were treated either with daily melatonin (250 μg/animal/day/i.p.) diluted in ethanol, only ethanol, or sterile saline solution. Rats were humanely killed at the 10th and 30th postoperative days. Plasma levels of Advanced Oxidation Protein Products (AOPP), Malondialdehyde (MDA), and Superoxide Dismutase (SOD) were measured. The number of osteoblasts, blood vessels and the area of new mineralized tissue formation were calculated in histologic sections. Results At the 10th day, DM+MEL (rats receiving both STZ and melatonin) group had significantly higher number of osteoblasts and blood vessels as well as larger new mineralized tissue surfaces (p<0.05 for each) when compared with DM group. At the 30th day, DM group treated with melatonin had significantly lower levels of AOPP and MDA than those of DM group (p<0.05). Conclusion Melatonin administration in STZ induced diabetic rats reduced oxidative stress related biomarkers and showed beneficial effects on bone healing at short term.

Efecto de la maca peruana (lepidium meyenii) y de la melatonina sobre el desarrollo testicular del ratón expuesto a hipoxia hipobárica continua / Effect of peruvian maca (lepidium meyenii) and melatonin on testicular development of mice exposed to continuous hypobaric hypoxia

El estudio de la hipoxia hipobárica (HH) determina un problema de salud pública y laboral en poblaciones que habitan en zonas de altura. La disminución del oxígeno afecta a diferentes órganos, incluyendo el testículo. El organismo responde frente a la hipoxia estimulando la angiogénesis, el flujo sanguíneo testicular e incrementa la temperatura intraescrotal, lo cual produce un daño de la espermatogénesis. Nuestro estudio valoró el efecto que produce la HH sobre el testículo del ratón. Se utilizó una cámara hipobárica regulada a 4.200 metros sobre el nivel del mar (msnm), en periodos de hipoxia durante 8,3; 16,6 y 24,9 días, en comparación a un grupo control en normoxia (500 msnm). En estos tres grupos, a unos ratones se administró melatonina, a otros maca (Lepidium meyenii) y a otros la combinación de melatonina y maca. Los objetivos fueron evaluar si la ingesta de maca protege al testículo, reduciendo el daño generado por la hipoxia, y determinar un posible efecto sinérgico de la melatonina y de la maca. La exposición a HH continua produjo una disminución del diámetro de los túbulos seminíferos y del lumen tubular; además, el seminograma demostró una reducción del recuento espermático, un aumento de la teratozoospermia y una reducción de la calidad del ADN espermático. La administración de maca aislada o la combinación de maca y melatonina en animales sometidos a HH produjo una notable mejoría de los parámetros relacionados con la función de los espermatozoides, siendo significativos la disminución del número de espermatozoides con morfología anormal y de la compactación del DNA, alcanzando en algunos casos valores próximos a los de los animales normóxicos. Los datos del presente modelo de HH corroboran los excelentes beneficios que la ingesta de maca tiene sobre la capacidad reproductiva de poblaciones que viven en áreas geográficas de grandes alturas.

Hypobaric hypoxia (HH) is a decisive factor in human health in populations that reside at high altitude levels. Low oxygen rate affects most tissues and organs, including the testis. In humans, hypoxia stimulates angiogenesis, testicular blood flow and increases intrascrotal temperature which determines negative effects on sperm production. Our study researched the effects of HH in mice testicle. Mice were housed in a hypobaric chamber with a setting at 4,200 m above sea level during three different periods of hypoxia (8.3, 16.6 and 24.9 days). Control groups were housed at normoxic conditions (500 m above sea level). Hypoxic mice were treated with melatonin, maca plant (Lepidium meyenii) and melatonin and maca combination. The aim of present study was to determine if maca consumption protects testis against harmful effects of hypoxia and to determine a possible synergistic effect between melatonin and maca administration. In this article we have demonstrated that hypoxia produces a considerable decrease of seminiferous tubules diameter and lumen diameter. Moreover, seminogram showed a reduced sperm count, increased teratozoospermia and a reduction of DNA quality. The HH mice treatment with maca or maca-melatonin combination showed statistically significant improvement at sperm function parameters, and in the reduction of sperm morphology abnormalities and DNA compaction, in some cases attaining rates closer to those registered in normoxic mice. Our experimental data corroborates that maca consumption improves reproductive capacity of populations that inhabit high altitude regions.

Protective role of melatonin in mouse spermatogenesis induced by sodium arsenite / Rol protector de la melatonina en el daño de la espermatogénesis en ratón producido por arsenito de sodio

Arsenic is a testicular environmental toxic. Melatonin (Me), being a potent antioxidant, may reduce the damage caused by arsenic in male fertility. The effects of daily oral exposure of Sodium Arsenite (As; 7.0 mg/kg/bw); Melatonin (Me, 10.0 mg/kg/bw); Me (10.0 mg/kg/bw) plus As (7.0 mg/kg/bw), and Negative Control (NaCl 0.9 percent) in male CF-1 adult mice were assessed in acute (8.3 days), chronic (33.2 days) and recovery (66,4 days) of testicular damage. We evaluated changes in testicular weight and histopathological, morphometric measurements, expression of COX-2 and Androgen Receptor (AR) antigens and lipid peroxidation levels. Treatment resulted in decreased tubular diameter and AR expression, and increased: interstitial area, luminal diameter, COX-2 expression levels and of lipid peroxidation. Co-administration of As and Me partially decreased germ cell degeneration and AR expression levels, improving testicular histopathological parameters. These results indicate that As causes toxicity and testicular germ cell degeneration by induction of oxidative stress. Me partially protects from this damage in mouse testis, acting as scavenger of oxygen radical species.

El arsénico es un tóxico testicular ambiental. La melatonina (Me), que es un potente antioxidante, puede reducir el daño causado por el arsénico en la fertilidad masculina. Se evaluaron los efectos de la exposición oral diaria de arsenito de sodio (As; 7,0 mg/kg/peso corporal), melatonina (Me, 10,0 mg/kg/p.c.); Me (10,0 mg/kg/p.c.) más As (7,0 mg/kg/pc) y el Control Negativo (NaCl 0,9 por ciento) en ratones adultos CF-1 machos, a los 8,3 días (exposición aguda), 33,2 días (crónica) y 66,4 días (recuperación) del daño testicular. Se evaluaron los cambios en el peso testicular y mediciones morfométricas, histopatológicas, expresión de COX-2, del receptor de andrógeno (AR) y los niveles de peroxidación de lípidos. El tratamiento con As resultó en disminución del diámetro tubular y la expresión de AR, y el aumento de: área intersticial, diámetro luminal, los niveles de expresión de COX-2 y peroxidación lipídica. La co-administración de As y Me disminuyó parcialmente la degeneración de células germinales, el aumento de los niveles de expresión de AR y hubo mejoría de los parámetros histopatológicos testiculares. Estos resultados indican que As es tóxico y causa degeneración de células germinales por inducción de estrés oxidativo. Me protege parcialmente este daño en los testículos de ratones, actuando como eliminador de especies radicalarias del oxígeno.

Effect of photoperiod and melatonin on volume and cellular parameters of testis in pinealectomized rats / Efecto del fotoperiodo y la melatonina sobre el volumen y parámetros celulares de los testículos en ratas pinealectomizadas

Mammalian reproductive axis is regulated by the combination of three fundamental tissues of neuroendocrine system including hypothalamus, hypophysis and gonads. In recent years, pineal gland has been included in this axis. The aim of the present study was to investigate the effect of 12L (Light):12D (Dark) photoperiod and melatonin administration (0.5 mg/kg/day; subcutaneously) on testicular volume and cellular parameters of testis at the pinealectomized (PE) rats. For this aim, twelve adult rats were firstly pinealectomized and then divided into two groups as GI and GII randomly. The GI rats served as control group and received only normal saline, whereas GII rats were the melatonin administered group. It was found that the total testicular volume, diameter and epithelial height of seminiferous tubules and number and nuclear diameter of the interstitial cells of the testes were increased in the GII. However, increase in the interstitial cell number was not found statistically significant among groups. In conclusion, it was observed that the 12L:12D photoperiod and doses of melatonin given increased the investigated parameters in PE rats.

El eje reproductivo de los mamíferos está regulado por la combinación de tres tejidos fundamentales del sistema neuroendocrino, incluyendo el hipotálamo, hipófisis y las gónadas. En los últimos años, la glándula pineal se ha incluido en este eje. El objetivo fue investigar el efecto del fotoperíodo 12L (Luz):12O (oscuridad) y la administración de melatonina (0,5 mg/kg/día, vía subcutánea) sobre el volumen testicular y los parámetros celulares del testículo en ratas pinealectomizadas (RP). Doce ratas adultas fueron pinealectomizadas y divididas en dos grupos, GI y GII de manera aleatoria. Las ratas del GI sirvieron como grupo de control y recibieron sólo solución salina normal, mientras que a las ratas del GII se les administró melatonina. Se encontró que el volumen total, diámetro y altura del epitelio de los túbulos seminíferos de los testículos, y el número y diámetro nuclear de las células intersticiales se incrementaron en el GII. Sin embargo, el aumento en el número de las células intersticiales no fue significativo entre los grupos. En conclusión, se observó que el fotoperíodo 12L:12O y la dosis administrada de melatonina aumentan los parámetros investigados en RP.

Protective role of melatonin and taurine against carbamazepine-induced toxicity in freshly isolated rat hepatocytes / Rol protector de la melatonina y taurina contra la toxicidad inducida por la carbamazepina en hepatocitos de rata recién aislados

Carbamazepine is widely used in a broad spectrum of psychiatric and neurological disorders. Idiosyncratic hepatotoxicity is a well-known adverse reaction associated with carbamazepine. Hepatotoxicity is rare, but a real concern when initiating therapy. It was found that oxidative stress is a potential mechanism for carbamazepine-induced hepatotoxicity. Present study evaluated the hepato protective role of taurine and melatonin against carbamazepine-induced hepatotoxicity. Hepatocytes were prepared by the method of collagenase enzyme perfusion via portal vein. Cells were treated with 400 uM carbamazepine, 1mM taurine, and 1mM melatonin. Cell death, reactive oxygen species formation, lipid peroxidation, and mitochondrial membrane depolarization were assessed as toxicity markers and the effects of taurine and melatonin administration on them were investigated. Our results showed that carbamazepine induced oxidative stress; increased ROS formation and lipid peroxidation products and also decreased mitochondrial membrane potential (DYm). Carbamazepine caused a decrease in cellular glutathione content and an elevation in oxidized glutathione levels. Our investigation showed that preincubation of hepatocytes with taurine (1 mM) could alleviate oxidative damages induced by carbamazepine; melatonin was also a good antioxidant to protect hepatocytes against cytotoxicity induced by carbamazepine. It may be concluded that taurine and melatonin are effective antioxidants to prevent carbamazepine-induced hepatotoxicity. Following our findings, further studies are suggested on the antioxidant effects of taurine and melatonin in patients receiving carbamazepine.

La carbamazepina es ampliamente utilizada en un gran espectro de trastornos psiquiátricos y neurológicos. La hepatotoxicidad idiosincrásica es una conocida reacción adversa asociada con la carbamazepina. La hepatotoxicidad es rara, pero es una preocupación real al iniciar el tratamiento. Se ha reportado que el estrés oxidativo es un potencial mecanismo para la hepatotoxicidad inducida por carbamazepina. El presente estudio evaluó la función hepato-protectora de la taurina y melatonina contra la hepatotoxicidad inducida por carbamazepina. Los hepatocitos se prepararon por el método de perfusión de la enzima colagenasa a través de la vena porta. Las células fueron tratadas con 400 uM de carbamazepina, 1 mM de taurina, y 1 mM de melatonina. La muerte celular, formación de especies reactivas de oxígeno (ERO), peroxidación de lípidos, y despolarización de la membrana mitocondrial fueron evaluadas como marcadores de toxicidad, junto con investigar los efectos de la taurina y melatonina administrada en ellos. Nuestros resultados mostraron estrés oxidativo inducido por carbamazepina, con aumento de las ERO, formación de productos de la peroxidación lipídica y disminución del potencial de membrana mitocondrial (DYm). La carbamazepina causó una disminución en el contenido celular de glutatión y una elevación de los niveles de glutatión no-oxidado. Se observó que la preincubación de los hepatocitos con taurina (1 mM) podría aliviar los daños oxidativos inducidos por carbamazepina; además la melatonina también fue un buen antioxidante para proteger a los hepatocitos. Se puede concluir que tanto la taurina y melatonina son antioxidantes eficaces para prevenir la hepatotoxicidad inducida por carbamazepina. Tras nuestros resultados, se sugiere estudiar los efectos antioxidantes de la taurina y melatonina en pacientes tratados con carbamazepina.