Comparison of the Effect of 8- and 12-Week Aerobic Exercise with Calorie Restriction on the Bax and Bcl-2 Expression in Rats with Non-alcoholic Fatty Liver Disease

Abstract

Background: In addition to oxidative stress, the apoptosis of liver cells plays a main role in non-alcoholic steatohepatitis pathogenesis. Nevertheless, the main mechanisms of the response of liver cell apoptosis in non-alcoholic steatohepatitis (NASH) models caused by a high-fat diet, as well as the effects of exercise with and without calorie restriction on these mechanisms, have not been assessed to date. Objectives: The present study aimed to investigate the effects of two exercise protocols with and without calorie restriction on apoptosis and liver damage in rats with non-alcoholic fatty liver disease (NAFLD). Methods: Sixty-four male Wistar rats were subjected to a high-fat diet for eight weeks and were divided randomly into eight groups: Control, calorie restriction (CR), aerobic exercise (AE), and aerobic exercise + calorie restriction (AC) for eight and twelve weeks. Also, two groups of rats that had normal and free access to food were named sham groups. The training groups exercised on the treadmill for five sessions a week for eight and twelve weeks. Two-way ANOVA was utilized for data analysis at a significance level of 0.05. Results: According to the findings, in both 8- and 12-week protocols, the expression of Bax proteins in the exercise and exercise + calorie restriction groups showed a significant decrease compared to the control group (P < 0.05). Also, Bcl-2 protein expression significantly increased in the exercise and exercise + calorie restriction groups than the control group (P < 0.05). The training groups showed no significant difference between the 8- and 12-week protocols. Conclusions: It was revealed that exercise with and without caloric restriction and independent of the protocol duration can improve the apoptosis of hepatocytes in NAFLD.