Obesity and insulin resistance are rapidly expanding public health problems. These disturbances are related to many diseases, including heart pathology. Acting through the Akt/mTOR pathway, insulin has numerous and important physiological functions, such as the induction of growth and survival of many cell types and cardiac hypertrophy. However, obesity and insulin resistance can alter mTOR/p70S6k. Exercise training is known to induce this pathway, but never in the heart of diet-induced obesity subjects. To evaluate the effect of exercise training on mTOR/p70S6k in the heart of obese Wistar rats, we analyzed the effects of 12 weeks of swimming on obese rats, induced by a high-fat diet. Exercise training reduced epididymal fat, fasting serum insulin and plasma glucose disappearance. Western blot analyses showed that exercise training increased the ability of insulin to phosphorylate intracellular molecules such as Akt (2.3-fold) and Foxo1 (1.7-fold). Moreover, reduced activities and expressions of proteins, induced by the high-fat diet in rats, such as phospho-JNK (1.9-fold), NF-kB (1.6-fold) and PTP-1B (1.5-fold), were observed. Finally, exercise training increased the activities of the transduction pathways of insulin-dependent protein synthesis, as shown by increases in Raptor phosphorylation (1.7-fold), p70S6k phosphorylation (1.9-fold), and 4E-BP1 phosphorylation (1.4-fold) and a reduction in atrogin-1 expression (2.1-fold). Results demonstrate a pivotal regulatory role of exercise training on the Akt/mTOR pathway, in turn, promoting protein synthesis and antagonizing protein degradation.

Exercise training has demonstrated cardioprotection effects. However, the exact mechanism behind this effect is not is clear. The present study evaluated the effects of 12 weeks of previous treadmill training on the levels of oxidative damage, antioxidant enzyme activity and injury in the myocardium of rats submitted to infarction induced by isoproterenol (ISO). Isoproterenol treatment (80 mg/kg given over 2 days in two equal doses) caused arrhythmias and 60% mortality within 24 h of the last injection in the control group (C + ISO) group when compared with the saline control group (saline). Creatine Kinase--MB levels were markedly increased in hearts from ISO-treated animals in the C + ISO group. Twelve weeks of treadmill training reduced superoxide production, lipid peroxidation levels and protein carbonylation in these animals, as well as increasing the activities and expressions of SOD and CAT. Previous training also reduced CK-MB levels and numbers of deaths by 40%, preventing the deleterious effects of ISO. Based on the data obtained in this study, it is suggested that 12-week treadmill training increases antioxidant enzymes, decreases oxidative damage and reduces the degree of infarction induced by ISO in the hearts of male rats.

Resumo -O futsal é uma modalidade esportiva que requer súbita aceleração e desaceleração com brusca mudança de direção. Este esporte expõe seus praticantes a grandes impactos, causando danos musculares e oxidativos. O objetivo desta pesquisa foi avaliar os níveis séricos de marcadores de danos musculares e oxidativos em atletas após jogo de futsal. Participaram do estudo, seis atletas de futsal, com idade média (21,2 ± 0,98 anos), peso (67,1± 5,5 kg) e altura (171,0 ± 0,07 cm). As coletas foram obtidas 30 minutos antes do jogo 1 (Pré-jogo); imediatamente após o jogo 1 (pós-jogo 1) e imediatamente após o segundo jogo (pós-jogo 2), que foi realizado 24 horas após o jogo 1. O soro foi utilizado para avaliações séricas de creatina quinase, dano protéico e lipídico. As concentrações de creatina quinase, peroxidação lipídica (xilenol) e carbonilação de proteína (carbonil) foram significativamente maiores após o término dos jogos 1 e 2, quando comparadas aos valores pré jogo. Os valores de sulfidrila foram menores após o término dos jogos 1 e 2, quando comparados aos valores pré jogo. Nenhuma diferença foi observada quando comparados os valores após jogo 1 e o jogo 2 em todos os parâmetros analisados. Coletivamente, os resultados demonstram que a partida de futsal provoca danos musculares e oxidativos. Surpreendentemente, não houve incremento nos parâmetros avaliados ao final do jogo 2. Devido ao reduzido conhecimento em relação ao tempo de recuperação após uma partida de futsal, acredita-se que este estudo seja de grande importância para os profissionais que trabalham com esse esporte.