Influence of hormonal estrogenic therapy and strength training on skeletal muscle of senile rats

Author(s)

Samuel Rodrigues Lourenço de Morais

• Document type: Doctoral Thesis
• Press: Araçatuba. 2016-10-05.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2016-08-22
• Advisor: Rita Cássia Menegati Dornelles; Patricia Chakur Brum; Antonio Musarò

Abstract

The decrease of estrogen (E2) circulating levels is strongly related to increased oxidative stress and the loss of muscle mass in elderly. The hormone replacement therapy (HRT) and strength training (ST) are the main effective interventions to prevent the loss of muscle mass, however, the mechanisms involved in interventions-induced benefits are not well elucidated. In this sense we evaluate the effect of HRT, ST and association on skeletal muscle maintenance of periestropaused rats. Female Wistar rats (18 months old) were randomly assigned into: non-exercised and non-treated group (NE-Veh), NE treated group (NE-E2), exercised and non-treated group (ST-Veh) and ST-E2 group. The animals received the HRT (17β estradiol; 2 x week; 50 µg/kg/week) and/or performed ST (3 x week, 80% overload) for 16 weeks. The HRT and ST promoted beneficial effects on skeletal muscle of periestropaused rats, however, by different manners. While HRT treatment leaves the reduction of oxidative stress (Dihidroetidine), the ST resulted in significate improvement on skeletal muscle function, in skeletal muscle antioxidant system (Catalase) and in miRNAs expression (2016, 146b and 133a). Already, the association of interventions resulted in improvement of redox state (Sirt1, Sirt3, PGC-1α, COXIV), in estrogen receptor responsiveness (ERα, ERβ and GPR30) and the activity of skeletal muscle signaling pathways (IGF-1/Akt-1/mTOR). In addition, the interventions, isolated or combinated, leaves an increase of the percentage of glycolytic fibers and reduced percentage of oxidative fibers. We suggest that the adherence to interventions (combinated or not) could minimize/attenuate the loss of skeletal muscle mass observed in later phases of aging process. (AU)

• FAPESP's process: 13/18907-2 - Estrogen and strength training influence on skeletal muscle morphology and oxidative stress of senile rats
• Grantee: Samuel Rodrigues Lourenço de Morais
• Support Opportunities: Scholarships in Brazil - Doctorate