Cardioprotective effect of L-carnitine in rats submitted to permanent left coronary artery ligation

Several studies have suggested that L-carnitine may limit the cellular alterations induced by myocardial hypoxia or ischemia. In the present study, rats were subjected to chronic treatment with L-carnitine (0, 25, 50 or 200 mg/kg/day i.p.) for 9 days prior to being submitted to permanent regional myocardial ischemia by left coronary artery ligation in situ. Following 48 hours of coronary occlusion, infarct size was measured using planimetry of transverse sections of the hearts, which had been stained with nitro-blue tetrazolium. Various functional and metabolic parameters have also been measured in isolated perfused hearts. Treatment with L-carnitine at 200 mg/kg/day i.p. for 9 days led to a significant reduction in infarct size and a better preservation of residual cardiac function. However, none of the metabolic parameters measured were modified. In conclusion, we suggest that the preservation of cardiac contractile function observed with L-carnitine pretreatment is secondary to carnitine-induced infarct size limitation.