Adaptações morfofuncionais e respostas moleculares do músculo esquelético de ratos submetidos ao treinamento resistido
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Data
2011-02-28
Autores
Aguiar, Andreo Fernando [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Embora fortes evidências demonstrem que os fatores de regulação miogênica (MRFs) e o fator de crescimento semelhante à insulina (IGF-I) apresentem um importante papel na resposta hipertrófica após treinamento resistido (TR) agudo, permanece desconhecido se a resposta dos MRFs e IGF-I também ocorre durante a adaptação ao TR a longo-prazo. Portanto, o objetivo deste estudo foi testar a hipótese de que a resposta hipertrófica e modulação das fibras do músculo esquelético após TR a longo-prazo poderia estar associada ao aumento na expressão gênica dos MRFs e IGF-I. Ratos Wistar (80 dias de idade, 250-300 g) foram divididos em quatro grupos: Controle 8 semana (C8, n = 8), Treinado 8 semanas (T8, n = 8), Controle 12 semanas (C12, n = 8) e Treinado 12 semanas (T12, n = 8). Os grupos T8 e T12 foram submetidos a um programa de TR progressivo (3 dias/semana) durante 8 e 12 semanas, respectivamente. O protocolo de treinamento consistiu de quatro séries de 10-12 repetições, com um período de descanso de 40 segundos entre cada série, realizado a 65-75% de uma repetição máxima (1RM). Ao término do experimento, os animais foram sacrificados e o músculo plantar coletado para as análises morfológica e molecular. O TR durante 8 e 12 semanas não promoveu qualquer alteração (p > 0,05) significante no ganho de peso corporal e consumo alimentar dos grupos T8 e T12 em relação aos grupos C8 e C12, respectivamente. Após 8 e 12 semanas de TR, a força absoluta (T8: 69,7% and T12: 126,0%, p < 0,05) e relativa (T8: 36,1% and T12: 57,7%, p < 0,05) foi significantemente elevada nos grupos T8 e T12, em comparação aos seus respectivos controles. No entanto, houve um similar aumento da área de secção transversal (AST) das fibras musculares (T8: 29% vs. T12: 35%, p > 0,05) entre os grupos T8 e T12, comparados aos grupos C8 e C12, respectivamente...
Although strong evidence show that the myogenic regulatory factors (MRFs) and insulin-like growth factor (IGF-I) have important roles in the hypertrophy response after acute resistance training, it is still unclear if response of MRFs and IGF-I also occurs during the adaptation to prolonged periods of resistance training (RT). Therefore, the purpose of this study was to test the hypothesis that fiber-types transition and hypertrophy during long-term RT could be associated with increased MRFs and IGF-I mRNA expression in the skeletal muscle. Male Wistar rats (80 days old, 250-300 g) were divided into four groups: 8 weeks control (C8, n = 8), 8-weeks trained (T8, n = 8), 12-weeks control (C12, n = 8), 12-weeks trained (T12, n = 8). T8 and T12 groups were submitted to a progressive RT program (3 day/week) for 8 and 12 weeks, respectively. The training protocol consisted of four sets of 10–12 repetitions, with a 40 s rest period between each set, performed at 65–75% of one repetition maximum (1RM). At the end of the experiment, animals were sacrificed and the plantaris muscle collected for morphological and molecular analysis. The RT did not change (p > 0.05) in body weight gain and food intake in the T8 and T12 compared to the C8 and C12 groups, respectively. After 8 and 12 weeks of RT, the absolute (T8: 69.7% vs. T12: 126.0%; p < 0.05) and relative (T8: 36.1% vs. T12: 57.7%; p < 0.05) strength (relative 1RM) was significantly elevated in the T8 e T12 groups, compared to respective control groups. RT for 8 and 12 weeks induced similar increase in myogenin (T8: 44.8% vs. T12: 37.7%; p > 0.05), MyoD (T8: 22.9% vs. T12: 22.3%; p > 0.05) and muscle fiber crosssectional area (CSA) (T8: 29% vs. T12: 35%; p > 0.05) in the T8 and T12, compared to C8 and C12 groups, respectively. After 8 weeks of RT, IGF-I increased in 30.1% in the T8 compared to C8 group, but returned to baseline after 12 weeks... (Complete abstract click electronic access below)
Although strong evidence show that the myogenic regulatory factors (MRFs) and insulin-like growth factor (IGF-I) have important roles in the hypertrophy response after acute resistance training, it is still unclear if response of MRFs and IGF-I also occurs during the adaptation to prolonged periods of resistance training (RT). Therefore, the purpose of this study was to test the hypothesis that fiber-types transition and hypertrophy during long-term RT could be associated with increased MRFs and IGF-I mRNA expression in the skeletal muscle. Male Wistar rats (80 days old, 250-300 g) were divided into four groups: 8 weeks control (C8, n = 8), 8-weeks trained (T8, n = 8), 12-weeks control (C12, n = 8), 12-weeks trained (T12, n = 8). T8 and T12 groups were submitted to a progressive RT program (3 day/week) for 8 and 12 weeks, respectively. The training protocol consisted of four sets of 10–12 repetitions, with a 40 s rest period between each set, performed at 65–75% of one repetition maximum (1RM). At the end of the experiment, animals were sacrificed and the plantaris muscle collected for morphological and molecular analysis. The RT did not change (p > 0.05) in body weight gain and food intake in the T8 and T12 compared to the C8 and C12 groups, respectively. After 8 and 12 weeks of RT, the absolute (T8: 69.7% vs. T12: 126.0%; p < 0.05) and relative (T8: 36.1% vs. T12: 57.7%; p < 0.05) strength (relative 1RM) was significantly elevated in the T8 e T12 groups, compared to respective control groups. RT for 8 and 12 weeks induced similar increase in myogenin (T8: 44.8% vs. T12: 37.7%; p > 0.05), MyoD (T8: 22.9% vs. T12: 22.3%; p > 0.05) and muscle fiber crosssectional area (CSA) (T8: 29% vs. T12: 35%; p > 0.05) in the T8 and T12, compared to C8 and C12 groups, respectively. After 8 weeks of RT, IGF-I increased in 30.1% in the T8 compared to C8 group, but returned to baseline after 12 weeks... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Musculos - Fisologia, Muscle fibers
Como citar
AGUIAR, Andreo Fernando. Adaptações morfofuncionais e respostas moleculares do músculo esquelético de ratos submetidos ao treinamento resistido. 2011. 74 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.