Studies of the cardioprotective effects of ascorbic acid in isolated rabbit hearts

Ascorbic acid (CAS 50-81-7) might mediate cardioprotective effects by scavenging free oxygen radicals. The effects of exogenous ascorbic acid on acute myocardial ischemia (MI) was investigated in isolated electrically-driven rabbit hearts (Langendorff, constant pressure: 70 cm H2O, Tyrode solution, Ca2+ 1.8 mmol/l, 37 degrees C). Repetitive MI, separated by a reperfusion period of 50 min, was induced by coronary artery branch ligature and quantitated from epicardial NADH-fluorescence photography. Starting after a reperfusion period of 20 min, isolated hearts were treated with ascorbic acid (10(-5) or 10(-4) mol/l). Ascorbic acid had no significant influence on the left ventricular left ventricular pressure or the coronary flow (p > 0.05). Ascorbic acid had no significant effect on epicardial NADH-fluorescence area or intensity (p > 0.05). Free radical scavenging properties reported for ascorbic acid do not mediate cardioprotective effects at the concentrations used in isolated rabbit hearts.