Sarcopenia, oxidative stress and inflammatory process in muscle of cirrhotic rats - Action of melatonin and physical exercise.

Sarcopenia is one of the most common features of cirrhosis, contributing to morbidity and mortality in this population. We aimed to evaluate the effect of melatonin (MLT) and exercise (EX) on the quadriceps muscle in rats with biliary cirrhosis induced by bile duct ligation (BDL). We used 48 males (mean weight = 300 g), divided into eight groups. A 20 mg/Kg MLT dose was administered via i.p. (1 x daily), and the EX, the animals were set to swim in couples for 10 min each day. Upon completion, blood, liver, and quadriceps samples were taken for analysis. In the liver enzymes analysis and comet assay results, a reduction was observed in the groups treated with MLT with/or EX comparing to the BDL group. In the evaluation of substances that react to thiobarbituric acid (TBARS), nitric oxide levels (NO), and tumor necrosis factor-alpha levels (TNF-α), there was a significant increase in the BDL group and a reduction in the treated groups. In the activity of the superoxide dismutase enzyme (SOD) and interleukin-10 levels (IL-10) concentrations, there was a significant increase in the treated groups of the BDL group. Histological analysis revealed muscle hypotrophy in the BDL group in comparison with the control group (CO) and increased muscle mass in the treated groups. There was an increase in weight gain and phase angle in the groups treated with MLT with/or EX comparing to the BDL group. We suggest that treatments may contribute to the reduction of muscle changes in cirrhotic patients.

Anti-inflammatory and antioxidant effect of melatonin on recovery from muscular trauma induced in rats.

In recent decades, the number of people who practice sports has grown exponentially, increasing the number of muscular injuries. Trauma injury occurs when the muscle is exposed to a sudden compression force. Melatonin (MLT) has often been cited in the literature as a potent antioxidant and anti-inflammatory agent. This study was designed to evaluate MLT action on muscle tissue in Wistar rats in an experimental model of muscle trauma. Twenty-eight Wistar rats were used, divided into four groups: CO (Control), CO + MLT (Control + Melatonin), T (Trauma) and T + MLT (Trauma + Melatonin). MLT (20 mg/kg) was administered (ip) daily at dusk until day 7. The trauma occurred on day 1, 2 h before the first MLT application. On day 8, muscle tissue was collected for histological analysis (HE), immunohistochemistry (TNF-α and NFκB), evaluation of oxidative stress through analysis of lipoperoxidation by TBARS and activity of SOD and GPx enzymes, and analysis of nitrites and nitrates. In the evaluation of TBARS and SOD, we observed a significant increase in the T group and a significant decrease in the T + MLT group. In the evaluation of GPx, there was a significant increase in the T group and a significant decrease in the T + MLT group. The histological analysis of muscle tissue revealed structural changes of muscle fibers and inflammatory infiltrate in the T group but a decrease in this damage in the T + MLT group. In the immunohistochemical evaluation, increased expression of TNFα and NFκB proteins in the T group was observed and a significant decrease of this expression in the T + MLT group. MLT was shown to attenuate oxidative damage and to diminish the expression of inflammatory proteins and tissue damage in this experimental model.