DIETARY FISH-OIL SUPPLEMENTATION ATTENUATES MYOCARDIAL DYSFUNCTION AND INJURY CAUSED BY GLOBAL-ISCHEMIA AND REPERFUSION IN ISOLATED RAT HEARTS

To determine the effect of dietary fish oil supplementation on myocard ial dysfunction following ischemia-reperfusion, independent of plasma and blood cells, Sprague-Dawley rats were fed fish oil-rich nonpurifie d diet or butter-enriched diet for 5 d. Myocardial content of long-cha in and (n-3) polyunsaturated fatty acids was greater in the fish oil-f ed rats (P < 0.01), whereas (n-6) fatty acid content was lower compare d with controls (P < 0.01). Platelet aggregation in fish oil-fed rats was also inhibited. Hearts from all rats were subjected to 15 min of g lobal ischemia and 10 min of reperfusion. In hearts of control rats, i schemia-reperfusion resulted in a marked decrease in force of cardiac contraction, increase in coronary perfusion pressure, appearance of ve ntricular arrhythmias and release of creatine kinase and thromboxane B 2 in the coronary effluent. Dietary fish oil supplementation attenuate d myocardial dysfunction induced by ischemia-reperfusion, as indicated by smaller change in force of cardiac contraction (-77% vs. -89%, P < 0.05) and coronary perfusion pressure (+37% vs. +7 1%, P < 0.001). Co ncomitantly, release of creatine kinase as well as thromboxane B2 in c oronary effluent was lower (P < 0.01). Ventricular arrhythmias occurre d less frequently in hearts from fish oil-fed rats. Thus, short-term d ietary fish oil supplementation attenuates myocardial dysfunction caus ed by ischemia-reperfusion by a direct effect on the heart independent of blood and plasma components.