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.