Effect of exercise training and L-arginine supplementation on oxidative stress and left ventricular function in rats with myocardial infarction

Introduction: The aim of the present study was to evaluate the effect of exercise training and L-arginine supplementation on oxidative stress and systolic ventricular function in rats with myocardial infarction (MI). Methods: Four weeks after the surgically-induced MI, 40 male Wistar rats were randomly assigned to the following 4 groups (n=10): MI-sedentary control (Sed) MI-exercise (Ex) MI-sedentary+L-arginine (Sed+LA) and MIexercise+ L-arginine (Ex+LA). The Ex and Ex+LA groups ran for 10 weeks on treadmill. Rats in the L-arginine-treated groups drank water containing 4% L-arginine. Before and after the training program, all subjects underwent resting echocardiography. Also catalase, glutathione peroxidase, malondialdehyde and myeloperoxidase were measured. Results: cardiac output, stroke volume and fractional shortening in Ex and Ex+LA groups were significantly increased compared to the Sed group. Cardiac systolic function in Ex+LA group was significantly greater than in Ex group. Infarct size was insignificantly reduced in response to exercise. Also, glutathione peroxidase activity was increased while malondialdehyde showed a decrease in response to exercise training, but no effect on myeloperoxidase and catalase was noted. There was no difference in enzyme activity between the training groups. Conclusion: Exercise training increased LV systolic function by decreasing oxidative stress and increasing antioxidant defense system in rats with myocardial infarction. It appears that L-arginine improves left ventricular function, but has no effect on oxidative stress indices.