The aim of the present study was to evaluate the effect of exercise training (ET) and L-arginine on ox-idative stress and ventricular function in rat with myocar-dial infarction (MI). Four weeks after the surgical procedures, 40 Wistar male rats were randomized to the following groups: MI-sedentary (Sed); MI-exercise (Ex);MI-sedentary ? L-arginine (Sed ? LA); and MI-exer-cise ? L-arginine (Ex ? LA); the rats were subjected to aerobic training in the form of treadmill running. Rats in the L-arginine-treated groups drank water containing 4 %L-arginine. Before and after the training program, all sub-jects underwent resting echocardiography. Catalase (CAT)glutathione peroxidase (GPx), malondialdehyde (MDA)and myeloperoxidase (MPO) were measured. Cardiac output, stroke volume and fractional shortening in Ex and Ex ? LA groups significantly increased in comparison with the Sed group. Cardiac systolic function indices in Ex ? LA group were significantly greater than Ex group. Also, GPx activity and MDA, respectively, increased and decreased in response to ET, but no change was observed in MPO and CAT. These results suggest that ET increased LV function by decreasing oxidative stress and increasing antioxidant defense system in rats with MI. In addition in response to training, L-arginine appears to have additive effect on cardiac function, but have no effect on oxidative stress indices.
