Impacto do treinamento resistido sobre o desenvolvimento de estresse do retículo endoplasmático no tecido muscular esquelético de ratos obesos

Abstract

The early exposure to high sucrose diets and sedentary lifestyle have been associated to metabolic disorders such as obesity. In this context, the skeletal muscle can suffer losses of mass, strength and recovery capacity and these changes may be related to induction of endoplasmic reticulum stress in this tissue. It is notorious that physical activity preserve and improve the lean mass. However, the molecular mechanisms of exercise training on ER stress in muscle is unclear. Thus, this work had the aim to evaluate the effect of resistance training (RT) on body composition, glycolipid metabolism and ER stress in the SM of male rats fed high-sucrose diet. Therefore, 28 weaned male Wistar rats were randomized into 2 groups: Control (CTR) and High-Sucrose Diet (HSD, 25% sucrose). At 17 weeks of life, each group was split into 2 new groups: CTR, CTR-T, HSD and HSD-T, where T means animals that performed RT protocol. In this protocol, the animals climbed 5 times a vertical ladder with 2 minutes rest between each climb and with 60% of the maximum weight attached to the tail, 3 times per week for 4 weeks. Body weight, food intake, Lee index, insulin resistance (TyG index) and the biochemical profile were assessed before and after the resistance training protocol. Gastrocnemius, soleus and EDL muscles and adipose tissues were collected to analyze of morphometry and/or gene expression. Results: The HSD group presented obesity and morphometric, metabolic imbalances, and increased ERE markers. The training reduced adipose tissue, prevented loss of lean, attenuated the biochemical parameters and reversed the ERE in the skeletal muscle. Conclusion: The early exposure to high sugar diet promoted morphometric and metabolic changes, and activation of ESR in skeletal muscle. Resistance training was able to attenuate and / or reverse the morphometric and metabolic disorders caused by high sugar diet and reversed the ERE in the skeletal muscle.