Increase of anti-oxidation by exercise in the liver of obese Zucker rats

1. The effects of endurance training on the anti-oxidant status in diabetes were studied using obese Zucker rats. 2. We used a moderate exercise programme consisting of treadmill running at 20 m/min and 0% incline for 1 h/day, 7 days/week, for 8 weeks. At the end of the experimental period, changes in hepatic anti-oxidant enzymes in terms of protein content and mRNA levels were detected using western blotting analysis and northern blotting analysis, respectively. In addition, anti-oxidant enzyme activity was determined. 2. A significant reduction in mRNA levels and the protein content of hepatic Mn-superoxide dismutase (SOD) and glutathione peroxidase (GPx) were observed in non-exercise obese groups, but the mRNA and protein levels of these enzymes were markedly increased after exercise training. In addition, exercise training reversed the decreased enzyme activities of Mn-SOD and GPx in obese Zucker rats. 3. The diabetes-related lowering of the glutathione (GSH) concentration was elevated in exercised obese Zucker rats, indicating a marked effect of regular moderate exercise on the endogenous anti-oxidant system. 4. There were no marked changes in hepatic Cu/Zn-SOD in terms of mRNA levels, protein content and activity in sedentary obese Zucker rats compared with their lean littermates. Endurance training did not modify the gene expression and activity of hepatic Cu/Zn-SOD. 5. The results of the present study suggest that regular moderate exercise could improve the anti-oxidant defence function of Mn-SOD, GPx and GSH in obese Zucker rats.