EFFECT OF ISCHEMIA REPERFUSION SEQUENCE ON CYTOSOLIC IRON STATUS AND ITS RELEASE IN THE CORONARY EFFLUENT IN ISOLATED RAT HEARTS/

The hypothesis that oxygen-derived free radicals play an important rol e in myocardial ischemic and reperfusion injury has received a lot of support. In the presence of catalytic amounts of transition metals suc h as iron, superoxide anions, and hydrogen peroxide can be transformed into a highly reactive hydroxyl radical degrees OH (Haber-Weiss react ion). In view of this, we have undertaken this study to investigate wh ether iron is involved in the reperfusion syndrome and therefore could aggravate free radicals injury. Coronary effluent iron concentrations and cardiac cytosolic iron levels were evaluated in rat hearts subjec ted to an ischemia/reperfusion sequences. In the case of total ischemi a, iron concentration in coronary effluents peaked immediately in the first sample collected upon reperfusion. However, in the case of parti al ischemia, iron concentration in coronary effluents peaked rather ex clusively during ischemia period. Cardiac cytosolic iron level augment ed significantly after 30 min of total ischemia and non significantly in the other ischemia protocols compared to perfused control hearts. I t also appears that the iron released is not protein-bound, and could therefore have a marked catalytic activity. The results of the present study suggest that in the oxygen paradox, iron plays an important rol e in inducing alterations during reoxygenation.