Efeito do exercício de ultra endurance sobre as reservas de glicogênio intramuscular e a expressão da proteína AMPK em ratos treinados
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Data
2011
Autores
Tarini, Victor Alexandre Ferreira [UNIFESP]
Orientadores
Faloppa, Flávio [UNIFESP]
Tipo
Tese de doutorado
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Durante o exercício dinâmico, as demandas de trifosfato de adenosina (ATP) aumentam significativamente e a sua reposição ocorre pelo catabolismo do glicogênio e ácidos graxos. Os efeitos do exercício sobre as reservas de glicogênio intramuscular já foram amplamente estudados. Porém, não se tem conhecimento sobre os efeitos do exercício de ultra endurance sobre o seu metabolismo. Nas últimas décadas a proteína AMPK tem sido descrita como um sensor das variações nas reservas de energia, sendo diretamente afetada pela contração muscular. O objetivo do presente estudo foi de verificar os efeitos do exercício de ultra endurance sobre as reservas de glicogênio muscular (GM) e a expressão da proteína AMPK. Métodos: vinte e quatro ratos wistar, machos, foram divididos aleatoriamente em 4 grupos (sedentário S=6, sedentário exaustão SE=6, treinado T=6 e treinado exaustão TE=6), onde T e TE correram progressivamente numa esteira rolante por 1,5 h/dia, 5d/semana durante 12 semanas (60% da Vmáx). Ao final SE e TE foram submetidos a um exercício de ultra endurance (60% de Vmáx) até a exaustão. O gastrocnêmio de ambas as patas foram retirados para análise do glicogênio por método colorimétrico e pela densidade ótica. A expressão gênica e protéica foi determinada por RT-PCR real time e por western blotting respectivamente. Resultados: Os grupos SE e TE apresentaram depleção significativa das reservas de GM (S =0,213 ± 0,003; T =0,203 ± 0,007; SE =0,031 ± 0,006; TE =0,028 ± 0,006 mg/g proteina) (p<0,001). O glicogênio hepático apresentou diferença significante nos grupos T e TE (S= 1,157 ± 0,09, SE= 1,002 ±0,05, T= 1,533 ± 0,05 e TE=1,037 ± 0,05) (p<0,05). O grupo TE apresentou diminuição significativa na glicemia (S=90,43 ± 2,47, SE=85,75 ± 3,18, T=84,84 ± 2,19 e TE=76,02 ± 5,60) (p<0,05). A expressão proteíca da AMPK aumentou em T e TE(p<0,05). Porém, a expressão gênica aumentou somente em TE (p<0,05). Conclusão: O exercício de ultra endurance depletou as reserva de GM predominantemente nas fibras musculares do tipo I. O treinamento de forma isolada afetou positivamente a expressão protéica da AMPK. Sendo mais evidente quando somado o fator exaustão.
During dynamic exercise, the adenosine triphosphate (ATP) demand increases significantly and its replacement occurs through the glycogen and fatty acids catabolism. The effects of exercise on intramuscular glycogen stores have been widely investigated. However, there is no information about ultra endurance exercise effects on muscle metabolism. In last decades 5’ adenosine monophosphate-activated protein kinase (AMPK) protein has been described as a sensor of changes in energy sources, being directly affected by muscle contraction. The aim of this study was to evaluate the effects of ultra endurance exercise on muscle glycogen (GM) stores and the expression of AMPK protein. Methods: twenty four male Wistar rats, were randomly divided into four groups (sedentary S= 6, sedentary exhaustion SE = 6, trained T =6, and trained exhaustion TE = 6), where T and TE groups run progressively on a treadmill 5d/wk for 12 weeks (60% Vmáx). At the end of training period SE and TE were submitted to an ultra-endurance exercise (60% Vmax) until exhaustion. The gastrocnemius of both legs were excised for glycogen analysis by colorimetric and by optical density method. Gene and protein AMPK expression was determined by real time RT-PCR and western blotting respectively. Results: SE and TE groups showed significant depletion of the GM storages (S = 0.213 ± 0.003, T = 0.203 ± 0.007, SE = 0.031 ± 0.006, TE = 0.028 ± 0.006 mg / g protein) (p <0.001). The liver glycogen was significantly lower in TE when compared to T group (p <0.05 ) (S = 1.157 ± 0.09, SE = 1.002 ± 0.05, T = 1.533 ± 0.05 and T = 1.037 ± 0.05). A significant decrease in plasma glucose was observed in TE group (p <0.05) (S = 90.43 ± 2.47, SE = 85.75 ± 3.18, T = 84.84 ± 2.19, and 76.02 ± TE = 5.60). The AMPK protein expression increased in T and TE groups (p <0.05). However, gene expression increased only in TE group (p <0.05). Conclusion: The ultra-endurance exercise depletes the GM reserves predominantly in type I muscle fibers. The training alone affected positively the protein expression of AMPK. This change was more evident when considered the exhaustion factor.
During dynamic exercise, the adenosine triphosphate (ATP) demand increases significantly and its replacement occurs through the glycogen and fatty acids catabolism. The effects of exercise on intramuscular glycogen stores have been widely investigated. However, there is no information about ultra endurance exercise effects on muscle metabolism. In last decades 5’ adenosine monophosphate-activated protein kinase (AMPK) protein has been described as a sensor of changes in energy sources, being directly affected by muscle contraction. The aim of this study was to evaluate the effects of ultra endurance exercise on muscle glycogen (GM) stores and the expression of AMPK protein. Methods: twenty four male Wistar rats, were randomly divided into four groups (sedentary S= 6, sedentary exhaustion SE = 6, trained T =6, and trained exhaustion TE = 6), where T and TE groups run progressively on a treadmill 5d/wk for 12 weeks (60% Vmáx). At the end of training period SE and TE were submitted to an ultra-endurance exercise (60% Vmax) until exhaustion. The gastrocnemius of both legs were excised for glycogen analysis by colorimetric and by optical density method. Gene and protein AMPK expression was determined by real time RT-PCR and western blotting respectively. Results: SE and TE groups showed significant depletion of the GM storages (S = 0.213 ± 0.003, T = 0.203 ± 0.007, SE = 0.031 ± 0.006, TE = 0.028 ± 0.006 mg / g protein) (p <0.001). The liver glycogen was significantly lower in TE when compared to T group (p <0.05 ) (S = 1.157 ± 0.09, SE = 1.002 ± 0.05, T = 1.533 ± 0.05 and T = 1.037 ± 0.05). A significant decrease in plasma glucose was observed in TE group (p <0.05) (S = 90.43 ± 2.47, SE = 85.75 ± 3.18, T = 84.84 ± 2.19, and 76.02 ± TE = 5.60). The AMPK protein expression increased in T and TE groups (p <0.05). However, gene expression increased only in TE group (p <0.05). Conclusion: The ultra-endurance exercise depletes the GM reserves predominantly in type I muscle fibers. The training alone affected positively the protein expression of AMPK. This change was more evident when considered the exhaustion factor.
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Citação
TARINI, Victor Alexandre Ferreira. Efeito do exercício de ultra endurance sobre as reservas de glicogênio intramuscular e a expressão da proteína AMPK em ratos treinados. 2011. 125 f. Tese (Doutorado em Ciências) - Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2011.