EXERCISE TRAINING REDUCES MYOCARDIAL LIPID-PEROXIDATION FOLLOWING SHORT-TERM ISCHEMIA-REPERFUSION

Purpose: The purpose of these experiments was to test the hypothesis t hat endurance exercise training will reduce myocardial lipid peroxidat ion following short-term ischemia and reperfusion (I-R). Methods: Fema le Sprague-Dawley rats (4 months old) were randomly assigned to either a sedentary control group (N = 13) or to an exercise training group ( N = 13). The exercise trained animals ran 4 d . wk(-1) (90 min . d(-1) ) at similar to 75% of (V) over dot O-2max. Following a 10-wk training program, animals were anesthetized, mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was achieved by a ligature around the left coronary artery; occlusion was maintained for 5 min followed by a 10-min period of reperfusion. Results: Although t raining did not alter (P > 0.05) myocardial activities of antioxidant enzymes (superoxide dismutase and glutathione peroxidase); training wa s associated with significant increases (P < 0.05) in heat shack prote in (HSP72) in the left ventricle. Compared with controls, trained anim als exhibited significantly lower levels (P < 0.05) of myocardial lipi d peroxidation following I-R. Conclusions: These data support the hypo thesis that exercise training provides protection against myocardial l ipid peroxidation induced by short-term I-R in vivo.