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

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). 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. 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. 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.