Action of melatonin and physical exercise on the liver of cirrhotic rats: Study of oxidative stress and the inflammatory process.

Background and aim: Cirrhosis is characterized by structural and functional alterations of the liver. Melatonin (MLT) has antioxidant properties. Physical exercise (EX) can reverse muscle loss in cirrhotic patients. The objective was to evaluate the action of MLT and EX on the liver of rats subjected to the experimental model of bile duct ligation (BLD).

Materials and methods: 48 male Wistar rats were used, divided into groups: Control (CO), CO+MLT, CO+EX, CO+MLT+EX, BDL, BDL+MLT, BDL+EX, and BDL+MLT+EX. The treatments occurred from the 15^th to the 28^th day. The dose of MLT was 20 mg/kg via I.p (1x/day), and the EX was performed 10 min/day. Blood and liver were collected for analysis.

Results: The liver integrity enzymes AST, ALT, and ALP showed a significant reduction in the groups treated with MLT and EX. Histological analyses showed reorganization of the liver parenchyma, reduction of inflammatory infiltrate, and fibrotic nodules. Lipoperoxidation (LPO), the activity of antioxidant enzymes, and nitric oxide metabolites showed a significant reduction in the groups treated with MLT and EX. The expression of TNF-α and NF-kB decreased in the treated groups.

Conclusion: Melatonin and physical exercise seem to be effective in restoring the parameters evaluated in this model of experimental cirrhosis.