Recent research advances in understanding the mechanisms and signaling pathways involved in the processes of recovery of muscle mass in old age, using different stimuli. These studies can contribute to the development of strategies to attenuate or block the loss of muscle mass associated with aging, such as physical training. In this context, several myogenic factors and signaling pathways that control the activity of satellite cells have been studied to further elucidate the events involved in the recovery process of muscle mass during aging. Among them stand out from the myogenic regulatory factors (MRFs), the hypertrophic pathway components (factor insulin-like growth (IGF-I), and myostatin (MSTN), which have been described as potential mediators of muscle growth. Thus, the purpose of this study is to assess the morphological and molecular responses of skeletal muscle of senile rats subjected to physical training after stimulation of atrophy. Therefore, will be used 64 male Wistar rats (18 months), divided into 8 groups (n = 8): C: control animals a week, I: Animals immobilized a week, C3: control animals 3 days; R3: Animals immobilized and recovered for 3 days, T3: Animals immobilized and submitted to exercise for 3 days; C7: Animals controls 7 days; R7: Animals immobilized and subsequently recovered by 7 days, T7: Animals immobilized and subsequently subjected to exercise for seven days. Initially, the animals in groups I, R3, R7, T3 and T7, will undergo a period of 7 days of immobilization of the hind limb. Muscle atrophy will be confirmed after a direct statistical comparison of the values of cross-sectional area (CSA) of muscle fibers studied in animals in groups I and C, sacrificed immediately after the immobilization period. Then the T3 and T7 groups, will undergo a rehabilitation program with muscle aerobic exercise (swimming) within 3 and 7 days respectively. The groups C, C3 and C7 are kept without any stimulus atrophic and not be subjected to exercise. At the end of the experiment the animals are sacrificed and the plantaris muscle removed and then subjected to morphological analysis, immunohistochemistry, and molecular biochemistry. The data will be submitted to appropriate statistical analysis.
News published in Agência FAPESP Newsletter about the scholarship: