Background & Objective: Diabetes is a metabolic disorder caused by low secretion or resistant to the insulin action. Oxidative stress, an imbalance between the free radical production and antioxidant defense systems of the body, is strongly related to diabetes and its symptoms. The aim of the present study is to evaluate effect of regular swimming on antioxidant system in diabetes.

Materials & Methods: Diabetes was induced by a single dose injection of streptozotocin (i.p, 50mg/Kg). Duration of exercise was 8 weeks. 40 male rats (200±20 g) were divided into four groups (control, control with exercise, diabetic, diabetic with exercise). At the end of experiments, rats were anesthetized by sodium pentobarbital (50mg/Kg) and blood samples were collected from the heart. Plasma and red blood cells were used to determine the super oxide dismutase (SOD), gluthathione peroxidase (GPX) and catalase (CAT) activities, and malonedialdehyde (MDA) levels.

Results: Diabetes significantly reduced SOD, GPX, and catalase activities in diabetic rats compared with control rats. MDA level, as a lipid peroxidation index, was increased significantly in diabetic-nonexercised rats compared to control. In response to exercise, MDA level decreased significantly in diabetic rats whereas SOD, GPX and catalase activities showed significant increases.

Conclusion: Swimming is beneficial in prevention of the hyperlipidemic symptoms and tissue injuries caused by oxidation stress in diabetes mellitus through increasing of the blood antioxidant enzyme activities, decreasing of the MDA level and reducing of the atherogenic index.