Image analysis of oxidative and glycolytic muscle fibers during reperfusion injury by segmentation based on regions / Análisis de imágenes de fibras musculares oxidativas y glucolíticas durante la reperfusión mediante segmentación basada en regiones

Different situations cause ischemia and reperfusion injury, affecting tissues under the level of compression. In this research, abnormal characteristics in distribution of muscle fibers types in soleus and extensor carpi radialis longus, during short periods of ischemia and short and long periods of reperfusion, were determined. Fibers were classified by enzyme histochemistry techniques NADH-TR and myosin-ATPase. Measurements of areas were carried out through semiautomatic image processing by using segmentation based on regions, which evidenced significant changes in distribution during reperfusion followed to one and three hours of ischemia, as well as in comparisons of areas for all periods of reperfusion. This study strengthens the evidence about using practical procedures of image analysis in the diagnosis of tisular abnormalities.

Diferentes situaciones causan isquemia y reperfusión afectando los tejidos que se encuentran por debajo del nivel de lesión. En esta investigación, se determinaron las características anormales en la distribución de los tipos de fibras musculares en los músculos sóleo y extensor radial longo del carpo, durante períodos cortos de isquemia y de reperfusión tanto cortos como prolongados. Las fibras se clasificaron mediante las técnicas de tinción de histoquímica enzimática NADH-TR y miosina-ATPasa. Las mediciones de las áreas realizadas mediante procesamiento de imágenes y el uso de la segmentación basada en regiones, evidenciaron cambios significativos en la distribución durante la reperfusión seguida a una y tres horas de isquemia, así como en las comparaciones para todos los períodos de reperfusión. Este estudio es un aporte en la evidencia sobre el uso de procedimientos prácticos de análisis de imágenes en el diagnóstico de alteraciones tisulares.

Morphological and morphometric study of the muscle fibers and neuromuscular junctions of the extensor digitorum longus in aged rats submitted to maternal protein restriction / Estudio morfológico y morfométrico de las fibras musculares y de las intersecciones neuromusculares del músculo extensor largo de los dedos de ratas de edad avanzada sometidas a la restricción proteica materna

Protein restriction implies the functional involvement of several systems and organs, including the skeletal muscle, because it is a protein reservoir in the body. This study sought to analyze the morphological and morphometric features of the muscle fibers and neuromuscular junctions (NMJs) of the extensor digitorum longus (EDL) muscle in rats at 365 days of age, submitted to maternal protein restriction during the gestation and lactation periods. Wistar rats were divided into two groups: a Control Group - mothers fed a normal-protein diet (17 % protein) during pregnancy and lactation; and a Restricted Group - mothers fed a low-protein diet (6 % protein) during pregnancy and lactation. The pups were kept with the mother throughout the lactation period (21 days), after which the offspring received a normal protein diet until 365 days of age. Histological (HE) and histoenzymological (NADH-TR) studies were conducted on the muscle fibers. The muscle was subjected to Nonspecific Esterase reaction to stain the Neuromuscular Junctions. Regarding the animals from the restricted group: the histologic analysis of the muscle fibers showed the presence of centralized nuclei and a diminished area; the histoenzymological study showed the different types of muscle fibers were randomly distributed in the EDL muscle and the area of the Type IIa muscle fiber was smaller; the ultrastructural study revealed disorganization of the Z line, and the presence of lipid droplets and vacuoles containing myelin figures in subsarcolemmal and intramiofibrilar regions; while the analysis of the NMJs exhibited no significant differences between the groups. Protein restriction in the pregnancy and lactation period may have affected the development of skeletal muscle, producing a permanent muscle-fiber deficit in the EDL muscle of the offspring.

La restricción proteica implica compromiso funcional de diversos sistemas y órganos, entre ellos, el músculo estriado esquelético, por ser una reserva de proteína del organismo. De esa forma, el presente trabajo procuró analizar las características morfológicas y morfométricas de las fibras musculares y de las intersecciones neuromusculares (JNMs) del músculo extensor largo de los dedos (EDL) en ratas de 365 días de edad, sometidas a restricción proteica materna durante los periodos de gestación y lactancia. Las ratas Wistar fueron separadas en dos grupos: El grupo Control - madres alimentadas durante la gestación y lactancia con ración normoproteica (17 % de proteína) y Grupo con restricción ­ madres alimentadas durante la gestación y lactancia con ración hipoproteica (6 % de proteína). Las crías permanecieron con la madre durante todo el periodo de lactancia (21 días) y después de este periodo la prole recibió ración normoproteica hasta los 365 días de edad. Se realizó un estudio histológico (HE) e histoenzimológico (NADH-TR) de las fibras musculares. Para la marcación de las JNMs, el músculo fue sometido a la reacción de Esterasa Inespecífica. El análisis histológico de las fibras musculares de los animales del Grupo con restricción mostró la presencia de núcleos centralizados y una disminución del área en el grupo con restricción. En el estudio histoenzimológico, el músculo EDL presentó una distribución aleatoria de los diferentes tipos de fibras musculares y el área de las fibras musculares del tipo IIa fue menor en el grupo con restricción. En relación al estudio ultraestructural, en los animales del grupo con restricción se observó desorganización de la línea Z, presencia de pequeñas gotas de lípidos y vacuolas que abrigaban figuras de mielina en las regiones subsarcolemal e intramiofibrilar. En el análisis de las JNMs no hubo diferencias significativas. La restricción proteica impuesta en el periodo de gestación y lactancia puede haber afectado el desarrollo del músculo esquelético, produciendo un déficit permanente en las fibras musculares del músculo EDL de la prole.

Effects of ischemic preconditioning and cilostazol on muscle ischemia-reperfusion injury in rats

PURPOSE: To evaluate effects of ischemic preconditioning and Cilostazol on muscle ischemia-reperfusion injury. METHODS: Male Wistar rats were submitted to muscle ischemic and reperfusion injury (4h of the left common iliac artery occlusion followed by 1h of reperfusion). Five experimental groups were constituted: Control group (n=4); Ischemia-Reperfusion (IR, n=5); Ischemic preconditioning group (IP, n=6); Ischemia-Reperfusion group treated with cilostazol (IRCi, n=6) and Ischemic preconditioning group treated with cilostazol (IPCi, n=6). At the end, left gracile muscle was removed and embedded in paraffin. Histopathology, neutrophil infiltration, myocyte necrosis and edema were analyzed. RESULTS: When compared with the control group, IR group showed increased neutrophil infiltration, severe necrosis and edema. There was significant difference between myocytes necrosis of IR group and IP group. There was no difference between the histopathological changes between IP, IRCi and IPCi groups. CONCLUSIONS: The model of IR caused severe muscle injury in the rat hind limb and ischemic preconditioning has a protective effect, reducing myocyte necrosis, however, treatment with cilostazol and also the association between cilostazol and preconditioning has no protective effect on the skeletal muscle subjected to ischemia and reperfusion injury. .

Morphologic alterations resulting from denervation of the diaphragm in rats / Alteraciones morfológicas resultantes de la denervación del diafragma en ratas

The morphological alterations that occur in the muscle fibers of denervated rat diaphragms were studied. Fifteen adult male albino rats (Rattus norvegicus) with a mean weight of 200 g and about 60 days of age were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by sectioning of the phrenic nerve and the right antimere served as control. Each antimere was divided into two fragments, which were used for histological (H.E.) and histoenzymological (NADH-TR and myofibrillar ATPase). After 4 weeks, denervated muscle fibers showed important light microscopic alterations: atrophy with angular profiles in cross-sections, cytoplasm containing vacuoles, enlarged interstitial space with increased connective tissue, cellular infiltration, and muscle fibers without defined contours. The most marked alterations being observed for type IIb and IIa fibers. Eight and 12 weeks after denervation, the NADH-TR reaction showed that it was impossible to characterize the muscle fibers based on their metabolic profile...

Fueron estudiadas las alteraciones morfológicas de las fibras musculares del diafragma denervado de ratas. Se utilizaron 15 ratas albinas (Rattus norvegicus) machos, adultos, con peso promedio de 200g y cerca de 60 días de edad. Se denervó el diafragma y después de 4, 8 y 12 semanas los animales fueron sacrificados. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en fragmentos, utilizados para el estudio histológico (H-E), histoenzimológico (NADH-TR y ATPasa miofibrilar). Después de 4 semanas las fibras musculares denervadas presentaron alteraciones importantes en lamicroscopía de luz: atrofia con perfiles angulados en secciones transversales; citoplasma con vacuolas; aumento del espacio intersticial con aumento de tejido conjuntivo; infiltración celular y fibras musculares sin contornos definidos, siendo las alteraciones más marcadas en las fibras tipo IIb e IIa. Después de 8 y 12 semanas de denervación la reacción para NADH-TR demuestra que es imposible caracterizar a las fibras musculares a través de su perfil metabólico...

Skeletal muscle major histocompatibility complex class I and II expression differences in adult and juvenile dermatomyositis

OBJECTIVE: To analyze major histocompatibility complex expression in the muscle fibers of juvenile and adult dermatomyositis. METHOD: In total, 28 untreated adult dermatomyositis patients, 28 juvenile dermatomyositis patients (Bohan and Peter's criteria) and a control group consisting of four dystrophic and five Pompe's disease patients were analyzed. Routine histological and immunohistochemical (major histocompatibility complex I and II, StreptoABComplex/HRP, Dakopatts) analyses were performed on serial frozen muscle sections. Inflammatory cells, fiber damage, perifascicular atrophy and increased connective tissue were analyzed relative to the expression of major histocompatibility complexes I and II, which were assessed as negatively or positively stained fibers in 10 fields (200X). RESULTS: The mean ages at disease onset were 42.0±15.9 and 7.3±3.4 years in adult and juvenile dermatomyositis, respectively, and the symptom durations before muscle biopsy were similar in both groups. No significant differences were observed regarding gender, ethnicity and frequency of organ involvement, except for higher creatine kinase and lactate dehydrogenase levels in adult dermatomyositis (p<0.050). Moreover, a significantly higher frequency of major histocompatibility complex I (96.4% vs. 50.0%, p<0.001) compared with major histocompatibility complex II expression (14.3% vs. 53.6%, p=0.004) was observed in juvenile dermatomyositis. Fiber damage (p=0.006) and increased connective tissue (p<0.001) were significantly higher in adult dermatomyositis compared with the presence of perifascicular atrophy (p<0.001). The results of the histochemical and histological data did not correlate with the demographic data or with the clinical and laboratory features. CONCLUSION: The overexpression of major histocompatibility complex I was an important finding for the diagnosis of both groups, particularly for juvenile dermatomyositis, whereas there was lower levels of expression of major histocompatibility complex II than major histocompatibility complex I. This finding was particularly apparent in juvenile dermatomyositis.

Effects of controlled and pressure support mechanical ventilation on rat diaphragm muscle / Efeitos da ventilação mecânica controlada e por pressão de suporte no músculo diafragma de ratos

PURPOSE: The objective of this study was to analyze the effects of Pressure Controlled Ventilation mode (PCV-C) and PSV mode in diaphragm muscle of rats. METHODS: Wistar rats (n=18) were randomly assigned to the control group or to receive 6 hours of PCV and PSV. After this period, animals were euthanized and their diaphragms were excised, frozen in liquid nitrogen and stored in at -80º C for further histomorphometric analysis. RESULTS: Results showed a 15 percent decrease in cross-sectional area of muscle fibers on the PCV-C group when compared to the control group (p<0.001) and by 10 percent when compared to the PSV group (p<0.05). Minor diameter was decreased in PCV-C group by 9 percent when compared with the control group (p<0.001) and by 6 percent when compared to the PSV group (p<0.05). When myonuclear area was analyzed, a 16 percent decrease was observed in the PCV-C group when compared to the PSV group (p<0.05). No significant difference between the groups was observed in myonuclear perimeter (p>0.05). CONCLUSION: Short-term controlled mechanical ventilation seems to lead to muscular atrophy in diaphragm fibers. The PSV mode may attenuate the effects of VIDD.

OBJETIVO: Avaliar os efeitos do modo ventilatório controlado por pressão controlada (PCV-C) e do modo PSV sobre o músculo diafragma de ratos. MÉTODOS: Ratos (n = 18) da linhagem Wistar foram distribuídos no grupo controle (RE) ou para receber AVM por 6 horas no modo PCV-C e no modo PSV. Após esse período, os animais foram eutanasiados, o diafragma retirado e encaminhado para a análise histológica e morfométrica. RESULTADOS: Os resultados revelaram uma redução da área das fibras musculares de 15 por cento no grupo PCV-C em comparação ao controle (p<0,001) e de 10 por cento quando comparado ao grupo PSV (p<0,05). Já com relação ao diâmetro menor observou-se uma redução de 9 por cento do grupo PCV-C em comparação ao controle (p<0,001) e de 6 por cento em relação ao grupo PSV (p<0,05). Quando avaliada a área dos mionúcleos, notou-se uma redução de 16 por cento desse parâmetro no grupo PCV-C, comparado ao PSV (p<0,05). Não houve diferença significativa no perímetro dos mionúcleos entre os grupos estudados (p>0,05). CONCLUSÃO: O grupo PCV-C apresentou atrofia muscular em um período curto de ventilação mecânica. O modo PSV parece atenuar os efeitos da DDIV.

Intramuscular 30 percent polymethylmethacrylate (PMMA) implants in a non-protein vehicle: an experimental study in rats / Implante intramuscular de polimetilmetacrilato (PMMA) 30 por cento, associado a veículo não-proteico: estudo experimental em ratos

INTRODUCTION: In the present study, the stability and biocompatibility of a 30 percent polymethylmethacrylate (PMMA) filling material implanted in the masseter muscle of rats were investigated according to the cytologic characteristics presented in the graft versus host reaction. METHODS: The study included 20 rats, which were divided into 4 groups: groups I, II, III, and IV corresponded to animals evaluated 7, 14, 45, and 60 days after surgery, respectively. The implant was placed in the right masseter muscle at the level of the mandibular angle. RESULTS: After 7 days, lymphoplasmacytic inflammatory infiltrates, a fibrous capsule, a large number of neutrophils, macrophages, and exudate were observed. The second group (14 days) showed granulation tissue composed of a lymphoplasmacytic inflammatory infiltrate, newly formed vessels, and a fibrous capsule. However, the second group also exhibited regeneration of the muscle fibers, and a decreased number of neutrophils and exudate. After 45 and 60 days, the inflammatory infiltrate decreased in intensity compared to the first 2 groups. CONCLUSIONS: The inflammatory reaction caused by PMMA is transient and does not compromise the function and the shape of the masseter muscle tissue, suggesting that PMMA is biocompatible.

INTRODUÇÃO: Este trabalho busca avaliar, em ratos, a estabilidade e a biocompatibilidade de um material de preenchimento à base de polimetilmetacrilato (PMMA) a 30 por cento implantado no músculo masseter, por meio do padrão, e a organização reacional no tecido receptor. MÉTODO: Foram utilizados 20 ratos, divididos em quatro grupos: grupo I, que correspondeu ao período de 7 dias de pós-operatório; grupo II, de 14 dias; grupo III, de 45 dias; e grupo IV, de 60 dias. O implante foi realizado no músculo masseter direito, na região do ângulo da mandíbula. RESULTADOS: No período de 7 dias, observou-se presença de infiltrado inflamatório linfoplasmocitário, com formação de cápsula fibrosa e presença de grande número de neutrófilos, macrófagos e formação de exsudatos. Em 14 dias, observou-se a formação de um tecido de granulação composto por infiltrado inflamatório linfoplasmocitário, vasos de neoformação e cápsula fibrosa. Porém, nesse tempo experimental, nota-se a regeneração das fibras musculares e a diminuição do número de neutrófilos e exsudatos. Após 45 dias e 60 dias, observou-se, no tecido muscular, diminuição da intensidade do infiltrado inflamatório, comparativamente aos tempos experimentais anteriores. CONCLUSÕES: A reação inflamatória provocada pelo PMMA é transitória e não compromete as funções e o contorno desse tecido muscular, o que sugere que o PMMA é biocompatível.

Fibroelastic components of the vesicourethral junction of rats in the aging process / Componentes fibroelásticos de la unión vesicouretral de ratas en el proceso de envejecimiento

The vesicourethral junction comprising the vesical trigone, is relevant in setting and positioning of the urinary bladder, along with the vesical neck, fixed by lateral ligaments of the bladder and tendinous arch of the pelvis fascia. Namely,the puboprostatic ligament (men) and the pubovesical (women). The circular set elastic fibers in this junction are important and valuable in the elasticity and plasticity of the area, allowing quick expansion and withdrawal with the flow of urine, and associated to smooth muscle tissue and nerve control form an important collective to maintain urinary continence. The objective of the present study is to describe the elastic system in the vesicouretral junction in relation to aging and its involvement in the states of urinary continence and incontinence, as well as the study of the vesicouretral junction in various age groups while evaluating with electron transmission microscopy. To carry out the study, 12 Wistar rats were used, divided into groups: neonate (4 animals), adult group (4 animals) and aged group (4 animals). Electron transmission microscopy with use of tanic acid technique associated to glutaraldehyde fixation, satisfactorily showed the extreme structural differences between mature elaunin and oxytalan fibers present between intercelular spaces and bundles of collagen fibers. The phases of elastogenesis in neonate animals and degradation of the elastic system of older animals were also evaluated.

La unión vesico-uretral, componente del trígono vesical, posee una relevante importancia en la fijación y posicionamiento de la vejiga urinaria conjuntamente con el cuello vesical, fijado por los ligamentos laterales de la vejiga y arco tendinoso de la fascia de la pelvis. Principalmente, sus componentes anteriores son: el ligamento puboprostático en los hombres y el ligamento pubovesical en las mujeres. Las fibras elásticas dispuestas circularmente en esta unión, son de valiosa importancia en la elasticidad y plasticidad de la región, permitiendo expansión y retiro rápido con el flujo de la orina, y asociado a musculatura lisa y control nervioso forman un conjunto importante para el mantenimiento de la continencia urinaria. Debido a existencia de puntos no esclarecidos en esta región en relación al sistema elástico y su participación en los estados de continencia/incontinencia urinaria, el presente trabajo tiene por objetivo el estudio de la unión vesico-uretral evaluándola en diferentes grupos etarios, a través de la microscopía electrónica de transmisión. Fueron utilizados 12 ratones Wistar, divididos en grupo de neonatos (4 animales), grupo adulto (4 animales) y grupo de ratones viejos (4 animales). La microscopía electrónica de transmisión, con uso de la técnica del ácido tánico asociado al fijador glutaraldeído, mostró satisfactoriamente las diferencias ultraestructurales entre las fibras elásticas maduras, elaunínicas y oxitalánicas, presentes entre los espacios intercelulares de las células musculares y haces de fibras colágenas, y también fases de elastogénesis en animales neonatos y envejecimiento y degradación del sistema elástico en los animales mayores.

Morphological changes in distant muscle fibers following thermal injury in Wistar rats / Alterações morfológicas das fibras musculares de um músculo distante da lesão térmica em ratos Wistar

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45 percent of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45 percent of the body surface.

OBJETIVO: A lesão térmica conduz o organismo a processos catabólicos a fim de reparar a área lesada. O propósito do presente estudo foi avaliar os efeitos da lesão térmica por escaldadura na morfologia das fibras musculares de um músculo distante da lesão. MÉTODOS: Foram utilizados 30 ratos Wistar, divididos em: Grupo submetido à lesão térmica por escaldadura (S) e Grupo Controle (C). A escaldadura foi provocada em 45 por cento da superfície corporal dos animais e padronizada pelo peso corpóreo. A eutanásia ocorreu nos períodos pós-lesão de quatro, sete e 14 dias. Retirou-se a parte média dos músculos gastrocnêmio medial os quais foram submetidos à técnica histológica de Hematoxilina-Eosina e Picrosírius. RESULTADOS: O aspecto poligonal das fibras musculares, com núcleos periféricos, bem como a distribuição eqüidistante das mesmas, característico das descrições da musculatura normal, verificado nos animais do grupo C não foi uma constante nas fibras do músculo dos animais do grupo S. Nestes, muitas fibras exibiram contorno arredondado, diferentes intensidades de marcação bem como maior distanciamento entre as mesmas. Observou-se ainda aumento substancial da quantidade de tecido conjuntivo no grupo S. CONCLUSÃO: Houve alteração da morfologia do músculo distante da lesão como resposta à lesão térmica de 45 por cento em modelo experimental.

Relación entre el tipo de fibra muscular esquelética del miembro posterior del caprino (Capra hircus) y su capacidad oxidativa y glicolítica / Relationship between skeletical muscular fiber type of the caprine (Capra hircus) hindlimb and the oxidative and glicolitic capacity

Se estudiaron con técnicas histoquímicas, los músculos de la cadera y el muslo del miembro posterior del caprino en condiciones de manejo semi-intensivo, con la finalidad de conocer la relación entre el tipo de fibra muscular y capacidad oxidativa y glicolítica de las mismas. Se tomaron muestras in vivo de los músculos gluteobíceps, glúteo medio, glúteo profundo, vasto intermedio, vasto lateral, gastrocnemios, soleo, semimembranoso, semitendinoso y tensor de la fascia lata, en cinco (5) cabras de 21-30 kg de peso. Las muestras se congelaron en isopentano enfriado en nitrógeno líquido. Los cortes se realizaron en un criostato a -20°C, con un espesor de 10 µm. Se utilizaron las técnicas de la Nicotamida Adenina Dinucleotido Deshidrogenada-Diaforasa (NADH-d) para determinar la capacidad oxidativa y la α-Glicero Fosfato Deshidrogenasa (α-GPD), para estudiar la capacidad glicolítica. El músculo vasto intermedio presentó 100 por ciento de fibras tipo I, casi todas de alta capacidad oxidativa. Los músculos glúteos medio y profundo, mostraron alrededor de 45 por ciento fibras tipo I, 22 por ciento de tipo IIa y 33 por ciento tipo IIb; aproximadamente la mitad de sus fibras presentaron alta capacidad oxidativa y entre media y baja capacidad glicolítica. El resto de los músculos tuvo un porcentaje alrededor de 29 por ciento de las fibras tipo I, 31 por ciento del tipo IIa y 40 por ciento del tipo IIb. En estos músculos se determinó un predominio de fibras con alta y mediana capacidad glicolítica.

With technical histochemical were studied, the muscles of the hip and the thigh of the hind limb of the goats under conditions of exploitation semi intensive with the purpose of knowing the relationship between of the different types of fibers and the oxidative and glicoltic capacity. They took samples in vivo of the muscles gluteal biceps, middle gluteal, deep glutea, vastus intermedius, vastus lateral, gastronemius, soleus, semimembranosos, semitendinosus and tensor facialatae in five (5) goats of 21-30 kg of weight. The samples froze in isopentano cooled in liquid nitrogen. The cuts were carried out in a cryostat to -20°C, with a thickness of 10 µm. The Nicotamida Adenosina Dehydrogenize diaphoreses (NADH-d) reactions were used to determine the capacity oxidative and the α-Glycerol Phosphate Dehydrogenize (α-GPD), to study the capacity glicolític. The muscle vast intermission presents 100 percent of fibers type I, almost all of high capacity oxidative. The muscles gluteus half and deep showed around 45 percent fibers type I, 22 type percent IIa and 33 percent type IIb; approximately half of their fibers they presented high capacity oxidative and between stocking and low capacity glicolítica. The rest of the muscles had a percentage around 29 percent of the fibers type I, 31 percent of the type IIa and 40 percent of the type IIb; in them there was a prevalence of fibers with high and medium capacity glicolítica.

Effects of exercise training on atrophy gene expression in skeletal muscle of mice with chronic allergic lung inflammation

We evaluated the effects of chronic allergic airway inflammation and of treadmill training (12 weeks) of low and moderate intensity on muscle fiber cross-sectional area and mRNA levels of atrogin-1 and MuRF1 in the mouse tibialis anterior muscle. Six 4-month-old male BALB/c mice (28.5 ± 0.8 g) per group were examined: 1) control, non-sensitized and non-trained (C); 2) ovalbumin sensitized (OA, 20 µg per mouse); 3) non-sensitized and trained at 50 percent maximum speed _ low intensity (PT50 percent); 4) non-sensitized and trained at 75 percent maximum speed _ moderate intensity (PT75 percent); 5) OA-sensitized and trained at 50 percent (OA+PT50 percent), 6) OA-sensitized and trained at 75 percent (OA+PT75 percent). There was no difference in muscle fiber cross-sectional area among groups and no difference in atrogin-1 and MuRF1 expression between C and OA groups. All exercised groups showed significantly decreased expression of atrogin-1 compared to C (1.01 ± 0.2-fold): PT50 percent = 0.71 ± 0.12-fold; OA+PT50 percent = 0.74 ± 0.03-fold; PT75 percent = 0.71 ± 0.09-fold; OA+PT75 percent = 0.74 ± 0.09-fold. Similarly significant results were obtained regarding MuRF1 gene expression compared to C (1.01 ± 0.23-fold): PT50 percent = 0.53 ± 0.20-fold; OA+PT50 percent = 0.55 ± 0.11-fold; PT75 percent = 0.35 ± 0.15-fold; OA+PT75 percent = 0.37 ± 0.08-fold. A short period of OA did not induce skeletal muscle atrophy in the mouse tibialis anterior muscle and aerobic training at low and moderate intensity negatively regulates the atrophy pathway in skeletal muscle of healthy mice or mice with allergic lung inflammation.

Efeito da desnutrição protéica pré e pós-natal sobre a morfologia, a diferenciação e o metabolismo do tecido muscular estriado esquelético em ratos / The effects of prenatal and postnatal malnutrition on the morphology, differentiation, and metabolism of skeletal striated muscle tissue in rats

OBJETIVO: Estudar características morfológicas, metabolismo e habilidades contráteis do músculo submetido a desnutrição protéica pré e pós-natal. MÉTODOS: Distribuição dos animais em dois grupos: controle, dieta normoprotéica (GC; n = 15; 5/5/5) e desnutrido, dieta hipoprotéica (GD; n = 15; 5/5/5), observados respectivamente no sétimo, 14º e 28º dia do período experimental. Foram avaliados massa corporal total, peso, habilidades contráteis e a morfologia do músculo tibial anterior. Amostras de tecidos com 8 m de espessura de ratos com idades de 7, 14 e 28 dias, corados por hematoxilina e eosina, e outros submetidos aos métodos histoquímicos nicotinamida adenina tetrazólio redutase (NADH-TR) e miofibrilar (m-ATPase) (pH = 4,4). RESULTADOS: Os pesos corporal e muscular apresentaram-se menores nos grupos desnutridos. Aos 7 dias de desnutrição, o músculo apresentou fibras com menor diâmetro, maior polimorfismo e maior teor de tecido conjuntivo endomisial. Nas histoquímicas, tipos de fibras sem delimitação segura. Aos 14 dias de desnutrição, fibras menores, mais polimórficas, muitas com núcleos centrais e moderado teor de tecido conjuntivo endomisial. Quanto à contração, a reação m-ATPase evidenciou fibras lentas e rápidas. A reação NADH-TR revelou os tipos de fibras slow oxidative, fast oxidative glycolytic e fast glycolytic. Aos 28 dias de desnutrição, fibras menores, agrupadas com contornos variáveis. Quanto ao tipo de contração e metabolismo, os três tipos de fibras apresentaram limites de reconhecimento indistinto. CONCLUSÃO: Os resultados experimentais sugerem que, além da redução no número de fibras, a desnutrição promove um retardamento na diferenciação das características morfológicas, metabólicas e contráteis dos tipos de fibras musculares esqueléticas em ratos na fase de crescimento.

OBJECTIVE: To study the contractile properties, metabolism and morphological characteristics of muscles submitted to prenatal and postnatal protein malnutrition. METHODS: Animals were distributed into two groups: Control, normoprotein diet (CG; n = 15; 5/5/5), and Malnourished, hypoprotein diet (MG; n = 15; 5/5/5), and examined on the 7th, 14th, and 28th days of the experiment. Total body mass, weight, and the contractile properties and morphology of the anterior tibial muscle were assessed. Several 8 µm-thick tissue samples were taken from 7, 14, and 28 day old rats and stained with HE or subjected to NADH-TR or m-ATPase (pH = 4.4) techniques. RESULTS: Body and muscle weight were lower in the malnourished group. On the 7th day of malnutrition, muscle samples exhibited fibers with smaller diameter, higher polymorphism and higher endomysial conjunctive tissue content. Histochemical methods were unable to precisely determine the types of fiber present. On the 14th day, there were smaller muscle fibers, more polymorphism, many of them with central nuclei and moderate endomysial conjunctive tissue content. With reference to contractile properties, the m-ATPase reaction identified both slow and fast fibers. The NADH-TR reaction revealed the following types of fiber: slow oxidative (SO), fast oxidative glycolytic (FOG) and fast glycolytic (FG). On the 28th day smaller, bunched muscle fibers varying shapes. All three types of fiber exhibited unclear recognition limits with respect to contraction and metabolism. CONCLUSION: Our experimental results suggest that, in addition to the reduction in numbers of fibers, malnutrition retards the differentiation of the morphological, metabolic, and contractile characteristics of skeletal muscle fibers in growing rats.

Fiber type composition in semitendinous muscle of Wistar rats and effects of intermittent training on its hypertrophy / Composición de los tipos de fibras del músculo semitendinoso de ratas Wistar y los efectos del entrenamiento intermitente en su hipertrofia

Skeletal muscles respond to several stimuli changing their phenotype. Muscular fibers adaptation capability is related to the presence of several myosin heavy chains (MHC). These express four types of pure fibers: I, IIA, IID and IIB containing MHCI, IIa, IId and IIb, respectively. Among pure fibers, there are hybrid fibers, which can express two or more types of myosins. In this study, types of fibers constituting male Wistar rats semitendinous and their myosin heavy chains, as well as influence of intermittent training on hypertrophy of these fibers have been checked through MATPase histochemical technique and electrophoretic proteins separation. All types of pure and hybrid muscular fiber have been found, however the fibers of the types IIA, IID and IIB were predominant, featuring muscle as a fast-contracting one. Training has promoted muscular fibers transition with a significant increase of fibers of IC, IIAD and IIDB type. A cross-section increase of fibers of IIDB and IIB type has also been noticed. In summary, semitendinous muscle is essentially constituted by fast-contracting fibers and training could promote transition and hypertrophy of these fast fibers.

Los músculos esqueléticos responden a diversos estímulos cambiando su fenotipo. La capacidad de adaptación de las fibras musculares está relacionada con la presencia de diversas miosinas de cadena pesada (MHC). Estas miosinas expresan cuatro tipos de fibras puras: I, IIA, IID, IIB, que contienen MHCI IIa IId IIb, respectivamente. Entre las fibras puras hay fibras híbridas, las cuales pueden expresar dos o más tipos de miosinas. En este trabajo, se observaron los tipos de fibras y las cadenas pesadas de miosinas del músculo semitendinoso en ratas Wistar macho, así como también, la influencia del entrenamiento intermitente en la hipertrofia de aquellas fibras, a través de la técnica histoquímica de mATPasa y separación eletroforética de proteínas. Todos los tipos de fibras musculares puras e híbridas fueron encontradas, siendo las fibras de tipo IIA IID y IIB predominantes, por ser un músculo de contracción rápida. El entrenamiento promovió la transición de las fibras musculares con un aumento significativo de las fibras del tipo IC, IIAD y IIDB. En una sección transversal, un incremento de fibras del tipo IIDB y IIB también fue reportada. En resumen, el músculo semitendinoso está compuesto esencialmente por fibras de contracción rápida y el entrenamiento puede promover la transición e hipertrofia de las fibras musculares rápidas.

Alteraciones musculares periféricas en la enfermedad de Chagas

La enfermedad de Chagas sigue siendo un problema en Venezuela y en varios países de Latinoamérica. Este trabajo presenta datos sobre las alteraciones que esta enfermedad produce en los músculos esqueléticos periféricos, lo cual puede contribuir a la incapacidad funcional que presentan muchos de los pacientes. Fueron estudiados 19 pacientes con enfermedad avanzada, a quienes se les hizo evaluación cardiorrespiratoria, ecocardiograma, prueba de ejercicio y biopsia del músculo cuádriceps. El 42% presentó incapacidad funcional moderada a severa, medida por el consumo máximo de oxígeno, que estuvo relacionada con cambios morfológicos y metabólicos en las fibras musculares. Se hallaron alteraciones en la microvasculatura muscular compatibles con daño autoinmune. En conclusión, los pacientes con enfermedad de Chagas sufren alteraciones en la musculatura periférica que puede contribuir a la incapacidad funcional y al grado de afectación por esta enfermedad. La determinación de la capacidad funcional debería agregarse a la evaluación de la enfermedad

Chagas disease is still a problem in Venezuela and other Latin American countries, in spite of efforts to control the disease. Peripheral muscle alterations that contribute to decreased functional capacity in moderate to advanced Chagas’ disease patients are analyzed in the present work. Nineteen Chagas’ disease patients were studied, including cardio-respiratory evaluation, echocardiogram, exercise test and quadriceps muscle biopsy. The results showed 42% patients with moderate to severe decrease of maximal oxygen consumption. Muscle biopsies presented morphologic and metabolic alterations, some related to functional capacity. Capillary vessel damage in muscle was similar to that found in autoimmune diseases. In conclusion, Chagas’ disease patients showed peripheral muscle alterations related to decreased functional capacity. The functional capacity changes may contribute to the severity of the disease and should be added to the evaluation of the patients

An interesting case report of Morvan's syndrome from the Indian subcontinent.

The French physician Augustine Marie Morvan first used the term 'la choriotae fibrillare' to describe a syndrome characterized by peripheral nerve hyperexcitability, dysautonomia, insomnia and fluctuating delirium. There are no published reports of the condition from the Indian subcontinent. We report the first such case from the region. Our patient, a 24-year-old male, presented with easy fatigability and stiffness in both the calves for 18 months; continuous twitching of muscles of all four limbs and jaw for two months; hyperhydrosis, palpitations, urinary symptoms, burning dysesthesia in hands, insomnia and abnormal sleep behavior for about a month. Patient had bilateral hyper-reflexia with extensor plantar on the right and equivocal response on the left. Electromyography revealed continuous muscle fiber activity. Thyroid function test, electroencephalography, computerized tomography scan (head) and routine cerebrospinal fluid analysis were normal. The patient showed marked clinical and electrophysiological improvement on prednisolone along with symptomatic therapy over the next two months.

Multi-minicore disease: a rare form of myopathy.

BACKGROUND: Multi-minicore disease is a rare form of myopathy characterized by slowly progressive or nonprogressive muscle weakness and characteristic multiple cores within the muscle fibers. To the best of our knowledge, this is first documentation of the clinicopathological features of this rare entity from India. MATERIALS AND METHODS: A ll cases of multi-minicore disease diagnosed in our laboratory were retrieved. Clinical and pathological features were reviewed. RESULT: During a period of two years (January 2004 to December 2005), we received 985 muscle biopsies for various reasons. Of which, 15 were diagnosed as myopathies and four of which were of multi-minicore disease. Thus, multi-minicore disease comprises 0.40% of all muscle diseases and 26.6% of all myopathies. All were male and presented in early childhood (first decade of life) with generalized hypotonia and muscle weakness. All of them had dysmorphic facies and three had high arched palate. CPK levels were normal and EMG was myopathic except in one patient. Microscopic examination revealed minimal changes with Type I fibers' predominance but characteristic multiple cores in the myofibers. Ultrastructural examination showed both structured and unstructured cores. CONCLUSIONS: Multi-minicore disease, although a rare form of myopathies, should be suspected in children who present with generalized hypotonia and slowly progressive muscle weakness along with dysmorphic facies.

Circumferential skin folds in a child: a case of Michelin tire baby syndrome.

A six-month-old girl who presented with dermatitis was found to have multiple, symmetric, deep, gyrate skin folds involving her trunk and similar circumferential lesions on her extremities since birth. She had a characteristic round face with hypertelorism, depressed nasal bridge, thin, down-turned vermillion border of upper lip and short neck. Skin biopsy demonstrated increased smooth muscle fibers in the deeper dermis. A diagnosis of Michelin tire baby syndrome was made. Clinical features, histopathology, differential diagnosis and prognosis of this rare disorder have been discussed.

A light microscopic study of fibrosis involving muscle in oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a common pre-malignant condition of the mouth in arecanut chewers in Indian subcontinent. It is characterized by restriction in opening of the mouth, tongue protrusion, and cheek flexibility. Reports of muscle changes in OSF, using light microscopy are few. Incisional biopsy sections of thirty OSF patients were stained with Masson's Trichrome stain, to study the fibrosis involving the muscle. Wide spectrum of changes were observed where fibrosis was being evident sub-epithelially, not extending in to the muscle to cases where only a few remnants of muscle fibers were seen and the missing muscle bundle area being replaced by fibrous tissue. The probable mechanism by which these changes occur is discussed.

Diagnosis of mitochondrial diseases: clinical and histological study of sixty patients with ragged red fibers.

BACKGROUND: Mitochondrial diseases are caused by mutations in mitochondrial or nuclear genes, or both and most patients do not present with easily recognizable disorders. The characteristic morphologic change in muscle biopsy, ragged-red fibers (RRFs) provides an important clue to the diagnosis. MATERIALS AND METHODS: Demographic data, presenting symptoms, neurological features, and investigative findings in 60 patients with ragged-red fibers (RRFs) on muscle biopsy, seen between January 1990 and December 2002, were analyzed. The authors applied the modified respiratory chain (RC) diagnostic criteria retrospectively to determine the number of cases fulfilling the diagnostic criteria of mitochondrial disease. RESULTS: The most common clinical syndrome associated with RRFs on muscle biopsy was progressive external ophthalmoplegia (PEO) with or without other signs, in 38 (63%) patients. Twenty-six patients (43%) had only external ophthalmoplegia, 5 (8%) patients presented with encephalomyopathy. Specific syndromes were the presenting feature in 8 (13%), Kearns-Sayre syndrome (KSS) in 4 and myoclonus epilepsy with ragged-red fibers (MERRF) in 4. Myopathy was the presenting feature in 5 (8%) and 4 presented with infantile myopathy. Of the 60 patients, 18 (30%) had proximal muscle weakness. Two patients with KSS and one patient with myopathy had complete heart block necessitating pace making. When the modified RC diagnostic criteria were applied, only 26 (43%) patients had one other major criterion in addition to RRFs for the diagnosis of mitochondrial diseases. The remaining 34 (57%) patients with RRFs on muscle biopsy had only some clinical features suggestive of RC disorder but did not fulfill the clinical criteria (of the modified diagnostic criteria) for the diagnosis of mitochondrial diseases. CONCLUSION: In patients with clinical features suggestive of RC disorder, demonstration of RRFs on muscle biopsy helps in confirming the diagnosis of mitochondrial disease in only a subgroup of patients.