The Effect of Aerobic Continuous Training on Myonectin, Insulin Resistance and Liver Enzymes in Rats with Nonalcoholic Fatty Liver Disease

Abstract

Background. Non-alcoholic fatty liver disease, is the most common reason of liver disorders that can be controlled by dieting and regular physical activity. Objectives. The aim of this study was to investigate the effect of aerobic continuous training on serum levels of myonectin, insulin resistance and liver enzymes in rats with non-alcoholic fatty liver disease. Methods. Thirty-four male Wistar rats (6 - 8 weeks old) were randomly assigned into two groups: normal diet (N = 9) and high-fat diet (N = 25). Through 12-week high-fat diet, induction of fatty liver was performed. In order to confirm non-alcoholic fatty liver induction, seven rats fed with high-fat diet were tested. The 18 remaining rats were randomly assigned to two groups: high-fat diet plus sedentary activity (n = 9) and high-fat diet plus aerobic continuous training (n = 9). The aerobic group has performed running on a treadmill at the intensity of 50 - 60% VO2max, for eight weeks and five sessions per week. The results were analyzed by one-way ANOVA and Tukey’s post hoc tests at the statistical significance level of p ≤ 0.05. Results. The significant body weight increase induced by high-fat diet was controlled by aerobic continuous training (p < 0.05). The serum levels of myonectin, insulin, glucose, alanine aminotransferase and aspartate aminotransferase enzymes and insulin resistance improved significantly after eight weeks of aerobic continuous training (p < 0.05). Conclusion. It seems that aerobic continuous training can improve insulin resistance and liver enzymes by reducing serum myonectin levels in rats with non-alcoholic fatty liver disease.