Efetividade da suplementação de melatonina segundo as revisões sistemáticas Cochrane / Effectiveness of melatonin supplementation according to Cochrane systematic reviews

Contextualização: A melatonina é um hormônio endógeno encontrado em quase todos os organismos e participa de vários processos fisiológicos. A suplementação de melatonina tem sido preconizada na mídia para o tratamento e prevenção de várias doenças. Entretanto, há carência de informações científicas disponíveis sobre seu real benefício para a saúde. Objetivos: Sumarizar as evidências de revisões sistemáticas da Cochrane, referentes à efetividade das intervenções com suplementação de melatonina em humanos. Métodos: Trata-se de overview de revisões sistemáticas Cochrane. Procedeu-se à busca na Cochrane Library (2023), sendo utilizado o descritor "MELATONIN". Todas as revisões sistemáticas de ensaios clínicos foram incluídas. O desfecho primário de análise foi a melhora clínica, a redução dos sintomas ou a prevenção da doença. Resultados: Oito estudos foram incluídos, totalizando 53 ensaios clínicos e 4.024 participantes. Houve evidência de efetividade apenas para controle de ansiedade em pacientes em pré-operatório (evidência moderada) em comparação com placebo e para prevenção e tratamento de jet lag de fuso horário (evidência alta de certeza). Discussão: Embora seja muito veiculada na mídia, a suplementação de melatonina carece de estudos de qualidade para análise de sua efetividade. Os estudos clínicos disponíveis até o momento são heterogêneos e apresentam limitações metodológicas. Poucas análises convergem com segurança para um bom nível de evidência que permita sua recomendação. Conclusão: Não há suporte com bom nível de evidência atualmente para a maioria das intervenções com suplementação de melatonina, sendo recomendada a realização de novos estudos prospectivos para melhor robustez dos achados e análises.

Therapeutic potential of stem cell and melatonin on the reduction of CCl4-induced liver fibrosis in experimental mice model / Potencial terapêutico de células-tronco e melatonina na redução da fibrose hepática induzida por CCl4 no modelo de ratos experimentais

Liver fibrosis is initial stage of any chronic liver disease and its end stage is develops into cirrhosis. Chronic liver diseases are a crucial global health issue and the cause of approximately 2 million deaths per year worldwide. Cirrhosis is currently the 11th most common cause of death globally. Mesenchymal stem cell (MSCs) treatment is the best way to treat acute and chronic liver disease. The aim of this study is to improve the therapeutic potential of MSCs combined with melatonin (MLT) to overcome CCl4-induced liver fibrosis and also investigate the individual impact of melatonin and MSCs against CCl4-induced liver impairment in animal model. Female BALB/c mice were used as CCL4-induced liver fibrotic animal model. Five groups of animal model were made; negative control, Positive control, CCl4+MSCs treated group, CCl4+MLT treated group and CCl4+MSCs+MLT treated group. Cultured MSCs from mice bone marrow were transplanted to CCl4-induced liver injured mice model, individually as well as together with melatonin. Two weeks after MSCs and MLT administration, all groups of mice were sacrificed for examination. Morphological and Histopathological results showed that combined therapy of MSCs+MLT showed substantial beneficial impact on CCl4-induced liver injured model, compared with MSCs and MLT individually. Biochemically, considerable reduction was observed in serum bilirubin and ALT levels of MLT+MSC treated mice, compared to other groups. PCR results shown down-regulation of Bax and up-regulation of Bcl-xl and Albumin, confirm a significant therapeutic effect of MSCs+MLT on CCI4-induced liver fibrosis. From the results, it is concluded that combined therapy of MSCs and MLT show strong therapeutic effect on CCL4-induced liver fibrosis, compared with MSCs and MLT individually.

A fibrose hepática é a fase inicial de qualquer doença hepática crônica, e em sua fase final desenvolve-se para cirrose. As doenças hepáticas crônicas são uma questão de saúde global crucial e a causa de aproximadamente 2 milhões de mortes por ano em todo o mundo. A cirrose, hoje em dia, é a 11ª causa mais comum de morte globalmente. O tratamento da célula-tronco mesenquimal (MSCs) é uma maneira eletiva de tratar a doença hepática aguda e crônica. O objetivo deste estudo é melhorar o potencial terapêutico dos MSCs combinados com a melatonina (MLT) para superar a fibrose hepática induzida por CCl4 e também investigar o impacto individual da melatonina e MSCs contra o comprometimento do fígado induzido por CCl4 no modelo animal. Os ratos BALB / C fêmeas foram usados ​​como modelo de animal fibrótico de fígado induzido por CCl4. Cinco grupos de modelo animal foram feitos: Controle Negativo, Controle Positivo, CCl4 + MSCs Tratados Grupo, Grupo Tratado CCl4 + MLT e Grupo Tratado CCl4 + MSCs + MLT. MSCs cultivados da medula óssea dos ratos foram transplantados para o modelo de camundongos de fígado induzido por CCl4, individualmente, bem como em conjunto com a melatonina. Duas semanas após a administração MSCs e MLT, todos os grupos de camundongos foram sacrificados para o exame. Os resultados morfológicos e histopatológicos mostraram que a terapia combinada do MSCs + MLT mostrou impacto benéfico substancial no modelo ferido no fígado induzido pelo CCl4, em comparação com o MSCs e o MLT individualmente. A redução bioquimicamente considerável foi observada em bilirrubina sérica e níveis ALT de ratinhos tratados com MLT + MSCs, em comparação com outros grupos. Os resultados de PCR mostraram regulação negativa do BAX e regulação positiva do BCL-XL e da albumina, confirmando um efeito terapêutico significativo do MSCs + MLT na fibrose hepática induzida por CCl4. Dos resultados, conclui-se que a terapia combinada de MSCs e MLT mostram um forte efeito terapêutico na fibrose hepática induzida por CCl4, em comparação com MSCs e MLT individualmente.

Melatonina, lactancia materna y sueño: revisión del tema / Melatonin, breastfeeding and sleep: topic review

Se revisa en el binomio madre-recién nacidos o/y lactantes, los diferentes ritmos circadianos, especialmente del sueño, la secreción de melatonina y las características de la leche materna. Se aconseja manejo para evitar la cronodisrupción

It is reviewed in the binomial mother-newborns or/and infants, the different circadian rhythms, especially sleep, melatonin secretion and the characteristics of breast milk. Handling is advised to avoid chrono disruption

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.

Time-dependent proregenerative effects of exogenous melatonin on the transected sciatic nerve / Efectos proregenerativos dependientes del tiempo de la melatonina exógena en el nervio ciático seccionado

SUMMARY: Microsurgical procedures are the treatment of choice of peripheral nerve injuries, but often fail to reach full functional recovery. Melatonin has neuroprotective actions and might be used as a possible proregenerative pharmacological support. Therefore, the aim of this study was to analyze the time-dependence of the neuroprotective effect of melatonin on the overall fascicular structures of both ends of the transected nerve. Sciatic nerve transection was performed in 34 adult male Wistar rats divided in four groups: two vehicle groups (N=7) treated intraperitoneally for 7 (V7) or 21 (V21) consecutive days with vehicle (5 % ethanol in Ringer solution) and two melatonin groups (N=10) administered intraperitoneally 30 mg/kg of melatonin for 7 (M7) or 21 (M21) consecutive days. At the end of the experiment, proximal stump neuroma and distal stump fibroma were excised and processed for qualitative and quantitative histological analysis. Intrafascicular neural structures were better preserved and the collagen deposition was reduced in the melatonin treated groups than in the vehicle groups. Myelin sheath regeneration observed through its thickness measurement was statistically significantly (p<0,05) more pronounced in the M21 (1,23±0,18 µm) vs. V21 group (0,98±0,13 µm). The mean volume density of the endoneurium was lower in both melatonin treated groups in comparison to the matching vehicle treated groups. Although not statistically different, the endoneural tube diameter was larger in both melatonin groups vs. vehicle groups, and the effect of melatonin was more pronounced after 21 days (24,97 % increase) vs. 7 days of melatonin treatment (18,8 % increase). Melatonin exerts a time-dependent proregenerative effect on nerve fibers in the proximal stump and an anti-scarring effect in both stumps.

Los procedimientos microquirúrgicos son el tratamiento de elección de las lesiones de los nervios periféricos, pero a menudo no logran una recuperación funcional completa. La melatonina tiene acciones neuroprotectoras y podría ser utilizada como un posible apoyo farmacológico proregenerativo. Por lo tanto, el objetivo de este estudio fue analizar la dependencia del tiempo del efecto neuroprotector de la melatonina sobre las estructuras fasciculares generales de ambos extremos del nervio seccionado. La sección del nervio ciático se realizó en 34 ratas Wistar macho adultas divididas en cuatro grupos: dos grupos de vehículo (N=7) tratados por vía intraperitoneal durante 7 (V7) o 21 (V21) días consecutivos con vehículo (5 % de etanol en solución Ringer) y dos grupos grupos de melatonina (N=10) a los que se les administró por vía intraperitoneal 30 mg/kg de melatonina durante 7 (M7) o 21 (M21) días consecutivos. Al final del experimento, se extirparon y procesaron el neuroma del muñón proximal y el fibroma del muñón distal del nervio para un análisis histológico cualitativo y cuantitativo. Las estructuras neurales intrafasciculares se conservaron mejor y el depósito de colágeno se redujo en los grupos tratados con melatonina respecto a los grupos con vehículo. La regeneración de la vaina de mielina observada a través de la medición de su espesor fue estadísticamente significativa (p<0,05) más pronunciada en el grupo M21 (1,23±0,18 µm) vs V21 (0,98±0,13 µm). La densidad de volumen media del endoneuro fue menor en ambos grupos tratados con melatonina en comparación con los grupos tratados con vehículo equivalente. Aunque no fue estadísticamente diferente, el diámetro del tubo endoneural fue mayor en ambos grupos de melatonina frente a los grupos de vehículo, y el efecto de la melatonina fue más pronunciado después de 21 días (aumento del 24,97 %) frente a los 7 días de tratamiento con melatonina (18,8 % de aumento). La melatonina ejerce un efecto proregenerativo dependiente del tiempo sobre las fibras nerviosas del muñón proximal y un efecto anticicatricial en ambos muñones.

Role of melatonin receptor 1B gene polymorphism and its effect on the regulation of glucose transport in gestational diabetes mellitus / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Melatonin receptor 1B (MT2, encoded by the MTNR1B gene), a high-affinity receptor for melatonin, is associated with glucose homeostasis including glucose uptake and transport. The rs10830963 variant in the MTNR1B gene is linked to glucose metabolism disorders including gestational diabetes mellitus (GDM); however, the relationship between MT2-mediated melatonin signaling and a high birth weight of GDM infants from maternal glucose abnormality remains poorly understood. This article aims to investigate the relationship between rs10830963 variants and GDM development, as well as the effects of MT2 receptor on glucose uptake and transport in trophoblasts. TaqMan-MGB (minor groove binder) probe quantitative real-time polymerase chain reaction (qPCR) assays were used for rs10930963 genotyping. MT2 expression in the placenta of GDM and normal pregnant women was detected by immunofluorescence, western blot, and qPCR. The relationship between MT2 and glucose transporters (GLUTs) or peroxisome proliferator-activated receptor γ (PPARγ) was established by western blot, and glucose consumption of trophoblasts was measured by a glucose assay kit. The results showed that the genotype and allele frequencies of rs10830963 were significantly different between GDM and normal pregnant women (P<0.05). The fasting, 1-h and 2-h plasma glucose levels of G-allele carriers were significantly higher than those of C-allele carriers (P<0.05). Besides, the protein and messenger RNA (mRNA) expression of MT2 in the placenta of GDM was significantly higher than that of normal pregnant women (P<0.05). Melatonin could stimulate glucose uptake and GLUT4 and PPARγ protein expression in trophoblasts, which could be attenuated by MT2 receptor knockdown. In conclusion, the rs10830963 variant was associated with an increased risk of GDM. The MT2 receptor is essential for melatonin to raise glucose uptake and transport, which may be mediated by PPARγ.

Research Progress in the Regulation of Follicle Development by Melatonin / 中国医学科学院学报

Melatonin,an endocrine hormone synthesized by the pineal gland,plays an important role in the reproduction.The growth and development of follicles is the basis of female mammalian fertility.Follicles have a high concentration of melatonin.Melatonin receptors exist on ovarian granulosa cells,follicle cells,and oocytes.It regulates the growth and development of these cells and the maturation and atresia of follicles,affecting female fertility.This paper reviews the protective effects and regulatory mechanisms of melatonin on the development of ovarian follicles,granulosa cells,and oocytes and makes an outlook on the therapeutic potential of melatonin for ovarian injury,underpinning the clinical application of melatonin in the future.

Protective effect of melatonin against oxygen-induced retinopathy: a study based on the HMGB1/NF-κB/NLRP3 axis / 中国当代儿科杂志

OBJECTIVES@#To study the protective effect of melatonin (Mel) against oxygen-induced retinopathy (OIR) in neonatal mice and the role of the HMGB1/NF-κB/NLRP3 axis.@*METHODS@#Neonatal C57BL/6J mice, aged 7 days, were randomly divided into a control group, a model group (OIR group), and a Mel treatment group (OIR+Mel group), with 9 mice in each group. The hyperoxia induction method was used to establish a model of OIR. Hematoxylin and eosin staining and retinal flat-mount preparation were used to observe retinal structure and neovascularization. Immunofluorescent staining was used to measure the expression of proteins and inflammatory factors associated with the HMGB1/NF-κB/NLRP3 axis and lymphocyte antigen 6G. Colorimetry was used to measure the activity of myeloperoxidase.@*RESULTS@#The OIR group had destruction of retinal structure with a large perfusion-free area and neovascularization, while the OIR+Mel group had improvement in destruction of retinal structure with reductions in neovascularization and perfusion-free area. Compared with the control group, the OIR group had significant increases in the expression of proteins and inflammatory factors associated with the HMGB1/NF-κB/NLRP3 axis, the expression of lymphocyte antigen 6G, and the activity of myeloperoxidase (P<0.05). Compared with the OIR group, the OIR+Mel group had significant reductions in the above indices (P<0.05). Compared with the control group, the OIR group had significant reductions in the expression of melatonin receptors in the retina (P<0.05). Compared with the OIR group, the OIR+Mel group had significant increases in the expression of melatonin receptors (P<0.05).@*CONCLUSIONS@#Mel can alleviate OIR-induced retinal damage in neonatal mice by inhibiting the HMGB1/NF-κB/NLRP3 axis and may exert an effect through the melatonin receptor pathway.

Research progress in control strategies of biological clock disorder / 生理学报

Circadian clock is an internal mechanism evolved to adapt to cyclic environmental changes, especially diurnal changes. Keeping the internal clock in synchronization with the external clock is essential for health. Mismatch of the clocks due to phase shift or disruption of molecular clocks may lead to circadian disorders, including abnormal sleep-wake cycles, as well as disrupted rhythms in hormone secretion, blood pressure, heart rate, body temperature, etc. Long-term circadian disorders are risk factors for various common critical diseases such as metabolic diseases, cardiovascular diseases, and tumor. To prevent or treat the circadian disorders, scientists have conducted extensive research on the function of circadian clocks and their roles in the development of diseases, and screened hundreds of thousands of compounds to find candidates to regulate circadian rhythms. In addition, melatonin, light therapy, exercise therapy, timing and composition of food also play a certain role in relieving associated symptoms. Here, we summarized the progress of both drug- and non-drug-based approaches to prevent and treat circadian clock disorders.

Role of selenoprotein M knockdown in the melatonin antagonism of nickel-induced apoptosis and endoplasmic reticulum stress in mouse heart / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The aim of this study was to investigate the role of selenoprotein M (SelM) in endoplasmic reticulum stress and apoptosis in nickel-exposed mouse hearts and to explore the detoxifying effects of melatonin. At 21 d after intraperitoneal injection of nickel chloride (NiCl2) and/or melatonin into male wild-type (WT) and SelM knockout (KO) C57BL/6J mice, NiCl2 was found to induce changes in the microstructure and ultrastructure of the hearts of both WT and SelM KO mice, which were caused by oxidative stress, endoplasmic reticulum stress, and apoptosis, as evidenced by decreases in malondialdehyde (MDA) content and total antioxidant capacity (T-AOC) activity. Changes in the messenger RNA (mRNA) and protein expression of genes related to endoplasmic reticulum stress (activating transcription factor 4 (ATF4), inositol-requiring protein 1 (IRE1), c-Jun N-terminal kinase (JNK), and C/EBP homologous protein (CHOP)) and apoptosis (B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), Caspase-3, Caspase-9, and Caspase-12) were also observed. Notably, the observed damage was worse in SelM KO mice. Furthermore, melatonin alleviated the heart injury caused by NiCl2 in WT mice but could not exert a good protective effect in the heart of SelM KO mice. Overall, the findings suggested that the antioxidant capacity of SelM, as well as its modulation of endoplasmic reticulum stress and apoptosis, plays important roles in nickel-induced heart injury.

Melatonin-Mediated Inhibitory Effect on Hyperimmune Status of Acquired Aplastic Anemia / 中国实验血液学杂志

OBJECTIVE@#To evaluate the expression level of melatonin and its effects on immune function in aplastic anemia (AA) patients.@*METHODS@#The enzyme-linked immunosorbent assay (ELISA) was used to detect the plasma levels of melatonin in AA patients, and the correlation between melatonin levels and laboratory indexs was analyzed. The activation, proliferation, and apoptosis of T cells from AA patients were analyzed by flow cytometry with or without melatonin in vitro.@*RESULTS@#The plasma levels of melatonin in AA patients were significantly lower compared with healthy controls (HC) (12.23 pg/ml vs 20.04 pg/ml, P < 0.01), while the plasma melatonin levels of AA patients in remission group after immunosuppressive therapy (IST) were significantly higher than those in non-remission group (29.16 pg/ml vs 11.73 pg/ml, P =0.04). Moreover, the melatonin levels were positively correlated with platelets (r =0.49), the absolute reticulocyte count (r =0.45), and the percentage of neutrophils (r =0.43). Meanwhile, there was a negative correlation between melatonin levels and the percentages of lymphocytes (r =-0.45). The expressions of CD25 and CD69 in both CD4+ and CD8+ T cells from AA patients were remarkably inhibited by melatonin in vitro (all P < 0.05). When cultured with melatonin, the proliferation rates of both CD4+ and CD8+ T cells from AA patients were markedly suppressed (P =0.01 andP < 0.01).@*CONCLUSION@#The plasma levels of melatonin were decreased in AA patients, which might play an important role in the mechanism of immunological abnormalities. The hyperimmune status of AA patients could be partially ameliorated by melatonin in vitro.

Research research on the use of melatonin in combination with therapeutic hypothermia for the treatment of neonatal hypoxic-ischemic encephalopathy / 中国当代儿科杂志

Neonatal hypoxic-ischemic encephalopathy (HIE) remains one of the leading causes of death and long-term neurodevelopmental disorders in full-term neonates, and there is currently no curative treatment. Therapeutic hypothermia is now a standard therapy for HIE in the neonatal intensive care unit, but its safety and efficacy in remote areas remains unclear. Melatonin is an indole endocrine hormone mainly produced by the pineal gland and it has the ability to easily penetrate the blood-brain barrier. Through receptor and non-receptor mechanisms, melatonin exerts anti-oxidative and anti-inflammatory effects and participates in the regulation of organelle function and the inhibition of cell death. Melatonin is considered one of the most promising drugs for the treatment of HIE based on its reliable safety profile and clinical/preclinical results. This article reviews the recent research on the use of melatonin in combination with therapeutic hypothermia for the treatment of neonatal HIE.

Melatonin promotes osteogenesis of bone marrow mesenchymal stem cells by improving the inflammatory state in ovariectomized rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effects of melatonin (MT) on bone mass and serum inflammatory factors in rats received ovariectomy (OVX) and to investigate the effects of MT on the levels of inflammatory factors in culture medium and osteogenic ability of bone marrow mesenchymal stem cells (BMSCs) stimulated by lipopolysaccharide.@*METHODS@#Fifteen 12-week-old Sprague Dawley (SD) rats were randomly divided into 3 groups. The rats in Sham group only received bilateral lateral abdominal incision and suture, the rats in OVX group received bilateral OVX, and the rats in OVX+MT group received 100 mg/(kg·d) MT oral intervention after bilateral OVX. After 8 weeks, the levels of serum inflammatory factors [interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)] were detected using ELISA assay. Besides, the distal femurs were detected by Micro-CT to observe changes in bone mass and microstructure, and quantitatively measured bone volume fraction, trabecular thickness, and trabecular number. The BMSCs were extracted from the femurs of three 3-week-old SD rats using whole bone marrow culture method and passaged. The 3rd-5th passage BMSCs were cultured with different concentrations of MT (0, 1, 10, 100, 1 000 µmol/L), and the cell viability was then detected using cell counting kit 8 (CCK-8) to select the optimal concentration of MT for subsequent experiments. Cells were devided into osteogenic induction group (group A) and osteogenic induction+1/5/10 μg/mL lipopolysaccharide group (group B-D). The levels of inflammatory factors (IL-1β, IL-6 and TNF-α) in cell culture medium were detected using ELISA assay after corresponding intervention. According to the results of CCK-8 method and ELISA detection, the cells were intervened with the most significant concentration of lipopolysaccharide for stimulating inflammation and the optimal concentration of MT with osteogenic induction, defining as group E, and the cell culture medium was collected to detect the levels of inflammatory factors by ELISA assay. After that, alkaline phosphatase (ALP) staining and alizarin red staining were performed respectively in groups A, D, and E, and the expression levels of osteogenic related genes [collagen type Ⅰ alpha 1 chain (Col1a1) and RUNX family transcription factor 2 (Runx2)] were also detected by real time fluorescence quantitative PCR (RT-qPCR).@*RESULTS@#ELISA and Micro-CT assays showed that compared with Sham group, the bone mass of the rats in the OVX group significantly decreased, and the expression levels of serum inflammatory factors (IL-1β, IL-6, and TNF-α) in OVX group significantly increased (P<0.05). Significantly, the above indicators in OVX+MT group were all improved (P<0.05). Rat BMSCs were successfully extracted, and CCK-8 assay showed that 100 µmol/L was the maximum concentration of MT that did not cause a decrease in cell viability, and it was used in subsequent experiments. ELISA assays showed that compared with group A, the expression levels of inflammatory factors (IL-1β, IL-6, and TNF-α) in the cell culture medium of groups B-D were significantly increased after lipopolysaccharide stimulation (P<0.05), and in a concentration-dependent manner. Moreover, the expression levels of inflammatory factors in group D were significantly higher than those in groups B and C (P<0.05). After MT intervention, the expression levels of inflammatory factors in group E were significantly lower than those in group D (P<0.05). ALP staining, alizarin red staining, and RT-qPCR assays showed that compared with group A, the percentage of positive area of ALP and alizarin red and the relative mRNA expressions of Col1a1 and Runx2 in group D significantly decreased, while the above indicators in group E significantly improved after MT intervention (P<0.05).@*CONCLUSION@#MT may affect the bone mass of postmenopausal osteoporosis by reducing inflammation in rats; MT can reduce the inflammation of BMSCs stimulated by lipopolysaccharide and weaken its inhibition of osteogenic differentiation of BMSCs.

Remote ischemic preconditioning-induced late cardioprotection: possible role of melatonin-mitoKATP-H2S signaling pathway

Purpose: Remote ischemic preconditioning (RIPC) confers cardioprotection against ischemia reperfusion (IR) injury. However, the precise mechanisms involved in RIPC-induced cardioprotection are not fully explored. The present study was aimed to identify the role of melatonin in RIPC-induced late cardioprotective effects in rats and to explore the role of H2 S, TNF-α and mitoKATP in melatoninmediated effects in RIPC. Methods: Wistar rats were subjected to RIPC in which hind limb was subjected to four alternate cycles of ischemia and reperfusion of 5 min duration by using a neonatal blood pressure cuff. After 24 h of RIPC or ramelteon-induced pharmacological preconditioning, hearts were isolated and subjected to IR injury on the Langendorff apparatus. Results: RIPC and ramelteon preconditioning protected the hearts from IR injury and it was assessed by a decrease in LDH-1, cTnT and increase in left ventricular developed pressure (LVDP). RIPC increased the melatonin levels (in plasma), H2 S (in heart) and decreased TNF-α levels. The effects of RIPC were abolished in the presence of melatonin receptor blocker (luzindole), ganglionic blocker (hexamethonium) and mitochondrial KATP blocker (5-hydroxydecanoic acid). Conclusion: RIPC produce delayed cardioprotection against IR injury through the activation of neuronal pathway, which may increase the plasma melatonin levels to activate the cardioprotective signaling pathway involving the opening of mitochondrial KATP channels, decrease in TNF-α production and increase in H2 S levels. Ramelteon-induced pharmacological preconditioning may also activate the cardioprotective signaling pathway involving the opening of mitochondrial KATP channels, decrease in TNF-α production and increase in H2 S levels.

Role of melatonin in attenuation of hemodynamic response to intubation and anesthetic requirements: a randomized, controlled, double-blind study

Abstract Background Melatonin has been studied to have anxiolytic, sedative, and analgesic effects. However, there is limited data on the effect of melatonin in the attenuation of hemodynamic response to intubation. We aimed to study whether preanesthetic oral melatonin attenuates hemodynamic responses to intubation and anesthetic requirements. Methods Sixty-four patients scheduled for laparoscopic cholecystectomy were randomized into melatonin or placebo group (n = 32 each). Melatonin group received two tablets (3 mg each) of melatonin, and the placebo group received two tablets of vitamin D3 120 min before induction. Hemodynamic parameters were recorded during induction and postintubation for 15 minutes. Total induction dose of propofol, total intraoperative fentanyl consumption, and adverse effects of melatonin were also noted. Results Postintubation rise in heart rate (HR) was less in the melatonin group compared to the placebo group (10.59% vs. 37.08% at 1 min, respectively) (p< 0.0001). Maximum percentage increase in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) was lesser in melatonin group than placebo group (SBP 9.25% vs. 37.73%, DBP 10.58% vs. 35.51%, MBP 9.99% vs. 36.45% at 1 min postintubation. respectively) (p< 0.0001). Induction dose of propofol (1.42 mg.kg-1 vs. 2.01 mg.kg-1) and the number of patients requiring additional fentanyl intraoperatively (3 vs. 11) were also significantly reduced in the melatonin group. Conclusion Premedication with 6 mg of oral melatonin resulted in significant attenuation of postintubation rise in HR, SBP, DBP, and MBP. It also reduced the induction dose of propofol, total intraoperative fentanyl consumption without any adverse effects.

Evaluation of the effect of melatonin in patients with Burning mouth syndrome: a double-blind, placebo-controlled randomized clinical trial

Abstract The present study was carried out to evaluate the effect of Melatonin and Placebo in the patient with the Burning mouth (BMs). This double-blind, placebo-controlled randomized clinical trial study was carried out on 30 patients who were suffering from BMS. During this period patients were divided into 2 study and control groups. The study group used four 3 mg Melatonin daily and the control group received a placebo. Then the severity of the burning sensation was measured by the physician Sleep quality was measured using the VAS scale using the Petersburg questionnaire. Data in the application Enter SPSS 20 and then using T test or equivalent Nonparametric was analyzed, mean sleep score and mean severity of oral irritation before and after treatment in two the group was evaluated using T-test Independent. Level significance was considered 0.05. The results of the present study show that the use of melatonin and a placebo in patients with BMS reduces sensation and improves their sleep quality, although it may not reduce it completely. In this study severity of burning was 4.93±2.56 after treatment in the study group and 6.93±2.12 in the control group, which was statistically significant (P =0.036). No significant difference was observed between the two groups in the sleep quality score (P-value = 0.43). Using Melatonin can be a reliable way to treat pain for which there is no standard treatment to date. Although evidence suggests an association between sleep disorders and BMS, melatonin was not superior to a placebo in reducing BMS-induced burning in the present study. Identification of stressors and the ways to struggle with them, further studies with larger samples and higher oral doses, extended follow-up periods and control of psychological factors, and measurement of body mass index that may affect pharmacokinetics are recommended.

Melatonin inhibits growth and metastasis of MDA-MB-231 breast cancer cells by activating autophagy / 南方医科大学学报

OBJECTIVE@#To investigate the effects of melatonin on the growth and metastasis of MDA-MB-231 breast cancer cells and explore the mechanism.@*METHODS@#MDA-MB-231 cells were treated with 1, 3 or 5 mmol/L melatonin, and the changes in cell proliferation were examined using CCK-8 assay. Colony-forming assay and wound healing assay were used to assess the effects of melatonin treatmnent on colony-forming ability and migration of the cells. Flow cytometry and immunofluoresnce assay were employed to examine apoptosis and positive staining for autophagy-related proteins in the cells treated with 3 mmol/L melatonin. The effects of melatonin treatment alone or in combination with 3-methyladenine (3-MA) on the expressions of the proteins associated with autophagy (LC3, P62 and Beclin1), apoptosis (Bcl2 and Bax) and epithelial-mesenchymal transition (E-cadherin and Snail) were examined with Western blotting.@*RESULTS@#Melatonin treatment significantly inhibited the proliferation of breast cancer cells in a concentration- and time-dependent manner (P < 0.05), suppressed colony-forming ability and migration (P < 0.01), and promoted apoptosis of the cells (P < 0.01). Melatonin treatment alone significantly increased the expressions of Bax (P < 0.05), E-cadherin, LC3-II/LC3-I, and Beclin1 and lowered the expressions of Bcl2 (P < 0.05), Snail, P62 (P < 0.05), and Bcl2/Bax ratio (P < 0.01) in the cells, and caused enhanced positive staining of Beclin1 protein and attenuated staining of P62 protein. Compared with melatonin treatment alone, melatonin treatment combined with 3-MA significantly decreased the expressions of Beclin1 (P < 0.001), LC3-II/LC3-I (P < 0.05), Bax (P < 0.01), and E-cadherin (P < 0.001) and increased the expressions of Bcl2 (P < 0.05), Snail, and Bcl2/Bax ratio (P < 0.01).@*CONCLUSION@#Melatonin can induce autophagy of MDA-MB-231 breast cancer cells to inhibit cell proliferation and metastasis and promote cell apoptosis, and suppressing autophagy can weaken the inhibitory effect of melatonin on the growth and metastasis of breast cancer cells.

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.

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) furthermore, T2 had similar expression of pro-apoptotic genes to CG (P < 0.05). ROS formation revealed that CG presented lower percentage of embryo surface area affected (3.80 ± 0.40%) (P < 0.05), in contrast, no differences were found among the other groups. T1 was most significantly (P < 0.05) damaged by DNA fragmentation. The vitrified groups with melatonin had similar damage levels of CG (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), além disso, T2 apresentou expressão semelhante as dos genes pró-apoptóticos de GC (P <0,05). A formação de EROS revelou que GC apresentou menor percentual de área de superfície embrionária afetada (3,80 ± 0,40%) (P <0,05), ao contrário, não foram encontradas diferenças entre os outros grupos. T1 foi mais significativamente (P <0,05) danificado pela fragmentação do DNA. Os grupos vitrificados com melatonina apresentaram níveis de dano semelhantes ao do GC (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.