Effects of dietary supplementation with fish oil on prostanoid metabolism during acute coronary occlusion with or without reperfusion in diet-induced hypercholesterolemic rabbits.

We studied the changes in myocardial and aortic concentrations of prostacyclin and thromboxane A2 during acute coronary occlusion with or without reperfusion in rabbits fed with a cholesterol-enriched diet with or without fish oil supplementation for a short (5 days) or long period (6 weeks). New Zealand white male rabbits were divided into 5 groups: Group I, 15 control rabbits fed with a laboratory standard rabbit chow. In addition to the standard chow, the 4 study groups were treated with cholesterol or fish oil. Group II, 17 rabbits fed with a 1% high cholesterol diet for 5 days. Group III, 16 rabbits fed with a diet containing 1% cholesterol and 10% fish oil for 5 days. Group IV, 17 rabbits fed with the same diet as group II for 6 weeks. Group V, 18 rabbits fed with the same diet as group III for 6 weeks. Each group of rabbits was randomly divided into the coronary occlusion or occlusion-reperfusion mode of experiment. Acute coronary occlusion was induced by ligating the marginal branch of the left circumflex coronary artery for 1 h. Subsequent reperfusion for 4 h was performed in the occlusion-reperfusion rabbits. The aortic tissue above the aortic valve and the ischemic and normal (nonischemic) areas of the left ventricle were excised for the measurement of 6-keto-PGF1 alpha and thromboxane B2 levels by radioimmunoassay. Both during coronary occlusion and occlusion-reperfusion, rabbits showed higher myocardial concentrations of 6-keto-PGF1 alpha and thromboxane B2 in the ischemic area than in the normal myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)