Effects of overtraining protocol based on eccentric contractions on the inflammatory and Mtor pathways in the heart of C57BL/6 mice

Abstract

The eccentric exercise-induced nonfunctional overreaching in mice is associated with low-grade chronic inflammation in skeletal muscle samples and serum. In addition, it is known that myocardium is also able to produce proinflammatory cytokines and that mTOR (mammalian target of rapamycin) pathway has a cardioprotector effect against these cytokines. However, the myocardium adaptations in response to EE-induced NFOR remain unknown. Thus, the main aim of the present investigation was to verify the effects of the overtraining (OT) protocol based on chronic sessions of EE on the content and activation of the proteins related to cardiac hypertrophy in mice - Akt (Protein kinase B) mTOR (mammalian target of rapamycin), S6K (S6 kinase), 4EBP1 (4E binding protein) - and on the content of the proinflammatory cytokines in mice cardiac muscle. The animals will be divided into 4 groups: naive (N, sedentary mice), control (CT, sedentary mice subjected to physical tests), trained (TR, mice subjected to the training protocol) and overtraining (OT, mice subjected to the OT protocol based on downhill running). The mice will be evaluated daily for variation in body weight and food intake. The content and activation of aforementioned proteins will be evaluated in the left ventricle of the heart muscle by the immunoblotting technique. For comparison between groups will be used variance analysis followed by test for multiple comparisons of means. A significance level of 5% will be used.