Efeitos do uso de Decanoato de Nandrolona sobre a junção neuromuscular de ratos em processo de envelhecimento submetidos ao exercício resistido
Arquivos
Data
2016-03-01
Autores
Valentino, Erick [UNESP]
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ISSN da Revista
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O envelhecimento populacional tem sido considerado um dos maiores desafios de saúde pública contemporânea, entre outros fatores leva à diminuição de hormônios, à perda progressiva da massa muscular e diminuição da força muscular. O exercício físico atua positivamente sobre esse sistema, bem como os derivados sintéticos da testosterona, os quais apresentam um efeito anabólico. Assim este trabalho teve como objetivo avaliar se a associação do exercício físico potencializado ou não por dose supra-fisiológica de decanoato de nandrolona previnem alterações decorrentes da idade no músculo sóleo de ratos e nas junções neuromusculares associadas. Foram utilizados 40 ratos Sprague-Dawley machos, com 90 dias de idade, os quais foram tratados durante 8 semanas e distribuídos, de acordo com o tratamento, em grupos de animais sedentários ou treinados, com ou sem o uso deDN. O treinamento físico foi realizado por sessões de saltos em água, três vezes por semana. Após atingirem 300 dias de idade, os músculos sóleos foram coletados e realizadas as seguintes análises: Análise morfológica e morfométrica das junções neuromusculares; Análise ultraestrutural das fibras musculares e junções neuromusculares associadas; Análise Imunohistoquímica e morfométrica das fibras Fast e Slow; Análise da Distribuição dos nAChRs por meio de microscopia confocal. Os resultados mostraram que houve diminuição do peso dos animais que fizeram uso de DN, embora o peso do músculo sóleo não tenha se alterado. A morfologia geral e morfometria das JNM se mantiveram constante nos grupos estudados, sendo que ultraestruturalmente as dobras juncionais eram escassas. Quanto à distribuição dos nAChRs , os animais que realizaram exercício, apresentaram um padrão de distribuição em de braços contínuos dos nAChR, nos demais o padrão em "ilha" estava presente. Na análise das fibras fast e Slow, o padrão morfométrico e quantitativo se mantiveram em todos os grupos experimentais. Sendo que núcleos centrais e áreas focais de lesão, bem como desorganização miofibrilar, foram observadas ultraestruturalmente nos animais que usaram DN. Os resultados permitem concluir que as alterações observadas neste estudo referem-se ao fator idade e que o exercício físico realizado na juventude manteve o padrão estrutural dos nAChR presentes nos jovens, já o DN não preveniu alterações morfológicas no sistema neuromuscular decorrente da idade.
Population aging has been considered one of the greatest challenges of contemporary public health; among other factors there is decreased hormone release, progressive loss of muscle mass, and decreased muscle strength. Physical exercise has a beneficial effect on that system, as well as synthetic testosterone derivatives, which have anabolic effect. This study had the objective of evaluating whether the association of physical exercise enhanced or not by supraphysiological dose of nandrolone decanoate prevents age-related alterations in the soleus muscle of rats and in the associated neuromuscular junctions. 40 male Sprague-Dawley rats, 90 days old, were treated for 8 weeks and distributed according to the treatment in sedentary or exercised group, with or without the use of ND. Physical training was conducted by jumps in water three times per week. At the age of 300 days, the soleus muscles were collected and analyzed as follows: morphologic and morphometric analysis of neuromuscular junctions; ultrastructural analysis of muscle fibers and associated neuromuscular junctions; immunohistochemistry and morphometric analysis of fast and slow-twitch fibers; analysis of the distribution of nAChRs by confocal microscopy. The results demonstrated that there was a decreased weight in the animals that used ND, although the weight of the soleus muscle did not change. The general morphology and morphometry of the NMJ remained constant in the groups studied, and in regard to ultrastructure the junctional folds were scarce. The animals that performed exercise had a pattern of nAChRs in continuous branches, in all the other animals the "island" pattern was present. The morphometric and quantitative pattern of slow and fast-twitch fibers remained stable in all groups. Central nuclei and focal areas of injury, as well as myofibrillar disorganization were observed in the animals that used ND. The results enable the conclusion that the alterations observed in this study were consequent to aging, and that physical exercise performed in youth maintained the structural pattern of nAChR present in the young animals. ND did not prevent morphological changes in the neuromuscular system consequent to aging.
Population aging has been considered one of the greatest challenges of contemporary public health; among other factors there is decreased hormone release, progressive loss of muscle mass, and decreased muscle strength. Physical exercise has a beneficial effect on that system, as well as synthetic testosterone derivatives, which have anabolic effect. This study had the objective of evaluating whether the association of physical exercise enhanced or not by supraphysiological dose of nandrolone decanoate prevents age-related alterations in the soleus muscle of rats and in the associated neuromuscular junctions. 40 male Sprague-Dawley rats, 90 days old, were treated for 8 weeks and distributed according to the treatment in sedentary or exercised group, with or without the use of ND. Physical training was conducted by jumps in water three times per week. At the age of 300 days, the soleus muscles were collected and analyzed as follows: morphologic and morphometric analysis of neuromuscular junctions; ultrastructural analysis of muscle fibers and associated neuromuscular junctions; immunohistochemistry and morphometric analysis of fast and slow-twitch fibers; analysis of the distribution of nAChRs by confocal microscopy. The results demonstrated that there was a decreased weight in the animals that used ND, although the weight of the soleus muscle did not change. The general morphology and morphometry of the NMJ remained constant in the groups studied, and in regard to ultrastructure the junctional folds were scarce. The animals that performed exercise had a pattern of nAChRs in continuous branches, in all the other animals the "island" pattern was present. The morphometric and quantitative pattern of slow and fast-twitch fibers remained stable in all groups. Central nuclei and focal areas of injury, as well as myofibrillar disorganization were observed in the animals that used ND. The results enable the conclusion that the alterations observed in this study were consequent to aging, and that physical exercise performed in youth maintained the structural pattern of nAChR present in the young animals. ND did not prevent morphological changes in the neuromuscular system consequent to aging.
Descrição
Palavras-chave
Idade, Junção neuromuscular, Fibra muscular, Exercicio fisico, Decanoato de nandrolona