Efeito da restrição de sono paradoxal no músculo plantar de ratos

• Ano de defesa: 2015
• Autor(a) principal: Dias, Guilherme dos Reis [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Sono; Músculo esquelético; Hormônios; Atrofia muscular
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=2724755; https://repositorio.unifesp.br/handle/11600/48939

Introduction: The skeletal muscle is important for the body because it is responsible for locomotion, posture maintenance, organ protection and for being a source of energetic substrates. Losses in this tissue involving protocols of sleep deprivation have been demonstrated. However, the possible changes when the sleep debt becomes chronic have not been described yet. Objective: Evaluate the effects of the paradoxical sleep restriction for 21 days in the plantar muscle of rats. Methods: Three-month old male rats Wistar EPM1 weighing between 300-350g were used. The animals were divided into two groups: control and paradoxical sleep restriction for 21 days. The protocol used to induce the sleep restriction was the modified method from multiple platforms. The animals stayed awake for 18 hours, they were put into the restriction tank at 4:00 pm and took out of it at 10:00 am of the next day. The animals were allowed to sleep only for 6 hours daily. After the 21st day, the animals were sacrificed and their blood and tissues (plantar muscle, fat, organs) were extracted. The blood samples were analysed for insulin, corticosterone, total testosterone, urea, creatinine and glucose levels. The mass of the liver, adrenal, spleen, fat (epididymal and retroperitonial) and plantaris muscle were also analysed. The following tests were carried out: the measurements of the cross-sectional area of muscle fibers; insulin-like growth factor 1 (IGF-1) analysis; quantification of the proteins involved in synthesis and degradation; and enzymatic activity of the proteasome 26S. Statistical data were performed using independent t test or ANOVA for repeated measures with post hoc Duncan. The significance value was p <0.05. Results: From the second day of the protocol, the body mass of the animals was found to be reduced in the group that was under sleep restriction compared to their mass in the first day. From the 8th day, this reduction was significant compared to the control group. There was atrophy of the plantar muscle, characterized by a reduction in the crosssectional area as well as in the muscle mass. The hormone concentrations were also found to have changed, there was a decrease in plasma insulin and a reduction of muscle IGF-1, and the corticosterone was increased in the sleep restriction group, which characterizes a catabolic environment. There were no significant changes in the protein synthesis pathway markers assessed and in the proteasome 26S activity. On the other hand, in the lysosomal autophagy pathway, the LC3 protein showed to be increased in sleep restriction group animals? muscles compared with the control group. Conclusion: The 21-day sleep restriction in Wistar rats can generate muscle atrophy, in which is possible to observe a decrease in the cross-sectional areas of muscle fibers and a decrease in muscle mass of the plantar muscle, with activation of the autophagy pathway.