Ethanol does not exert myocardial preconditioning in an intact rabbit model of ischemia/reperfusion

Some epidemiologic analyses suggest that moderate drinking of alcohol may have beneficial effects on the heart. An experimental in vitro study also indicated that acute alcohol administration may precondition myocardium against ischemia, but only if it is washed out before ischemia. The goal of this study was to test whether alcohol + washout preconditions the myocardium to ischemia, reducing necrosis after ischemia/reperfusion in an in vivo model. Two groups of anesthetized open-chest rabbits received ethanol (0.5 mL/kg, intravenously) at 90 minutes before (Group 1, alcohol preconditioning, n = 8) or 5 minutes before (Group 2, acute, n = 8) coronary artery occlusion (CAO); control rabbits received saline (Group 3, n = 8). All rabbits received 30 minutes of CAO and 3 hours of reperfusion. Blood alcohol level at the time of CAO in Group 1 had returned to control level (< 10 mg/dL). Alcohol level in Group 2 was 162 +/- 9 mg/dL. There were no differences in hemodynamics, ischemic risk region size, or collateral blood flow among groups. Alcohol, with or without washout, failed to reduce necrosis. Infarct size (% risk region) was 45 +/- 5% in control rabbits, 48 +/- 6% with acute administration, and 53 +/- 7% with washout (P = 0.57). These data indicate that alcohol + washout did not precondition hearts against ischemia in this model, adding evidence to the theory that acute alcohol administration has no direct beneficial effect on ischemic myocardium.