Efeito de diferentes doses de nandrolona associado ao treinamento de for a sobre o perfil fenotípico e área de sec o transversa do músculo de ratos Effect of different doses of nandrolone associated with resistance training on muscle phenotypic profi le and cross-sectional area of rats

O presente estudo avaliou a influência de diferentes doses de decanoato de nandrolona (DN) associado ao Treinamento de For a (TF) sobre o fenótipo de fibras e área de sec o transversa (AST) do músculo extensor longo dos dedos (EDL) em ratos "Wistar". Os animais foram divididos em sete grupos: controle (GC) e grupos de acordo com a concentra o de DN (0,1, 1, 2, 5, 10 e 20 mg/kg) administrada intramuscular 3 vezes/semana. O TF consistiu de saltos em meio líquido (carga 50-70% do peso corporal) 3x/semana, durante cinco semanas. A associa o do TF e DN promoveu a o modulatória sobre os tipos de fibras. Houve hipertrofia das fibras de contra o rápida (tipo II) em compara o com as fibras de contra o lenta (tipo I). Em conclus o, apesar da associa o do TF com DN aumentar a AST muscular e alterar o fenótipo das fibras, n o houve efeito gradual das doses mais altas. The aim of the present study was to evaluate the influence of different doses of nandrolone decanoate (ND) associated with Strength Training (ST) on the phenotype of fibers and cross-sectional area (CSA) of the extensor digitorum longus (EDL) in Wistar rats. The animals were divided into seven groups: control (CG) and the groups according to the dose of ND administered (0,1, 1, 2, 5, 10 e 20 mg/kg). The ST consisted of water jumping with loads of 50-70% of their body mass, three times per week during five weeks. The association of ST with ND promoted a modulatory role on the muscle fiber types. There was a hypertrophy of fast twitch fibers (type II) as compared with slow twitch (type I). In conclusion, although the association of ST with ND increased muscle CSA and modified fiber phenotype, there was no additional effect of higher doses.