EFFECT OF VITAMIN-A AND VITAMIN-E ON ISCHEMIA-REPERFUSION DAMAGE IN RABBIT HEART

The aim of this study was to test the effect of vitamins A and E in re ducing oxyradical effects and myocardial damage after ischemia - reper fusion in the rabbit heart. Oxyradical effects were indirectly assesse d by hydroperoxide initiated chemiluminescence and myocardial damage w as evaluated by qualitative and quantitative electron microscopy. Left anterior coronary artery was ligated in control and vitamin-treated r abbits for 30 min and then reperfused for 10 min. Rabbits were pretrea ted with 150 mg vitamin E and 60000 IU vitamin A 24 h before surgery, After 10 min of reperfusion full-thickness needle samples were obtaine d from five different myocardial areas (three ventricular and two sept al areas) and used for the determination of hydroperoxide-initiated ch emiluminescence and ultrastructural damage. In the control group, hydr operoxide-initiated chemiluminescence was 18400 +/- 500 cpm/mg protein for the non-ischemic and non-reperfused ventricular areas, and 40500 +/- 1800 cpm/mg protein for ischemic-reperfused ventricular areas. In the vitamin-treated group, hydroperoxide-initiated chemiluminescence w as decreased by 8% in the non ischemic acid non reperfused ventricular areas and by 51-75% in the ventricular ischemic and reperfused areas. The two septal areas in the control group gave chemiluminescences of 6800 +/- 1200 cmp/mg protein (non ischemic-non reperfused) and 17000 /- 2000 cpm/mg protein (ischemia-reperfusion). In the vitamin-treated group, chemiluminescence decreased by 4 and 58%, respectively. The isc hemia-reperfused areas showed extensive edema, margination of nuclear chromatin and swollen mitochondria with disrupted cristae including ru pture of the inner and outer mitochondrial membranes. Assessment of mi tochondrial damage in electron micrographs by stereological counting a nd grading indicated 77% of damaged mitochondria. These hearts display ed the early signs of irreversible damage and infarction. Rabbits pret reated with vitamins A and E showed a 18% of damaged mitochondria in t he same areas (p < 0.001) and relative preservation of myocyte subcell ular structures. The results indicated that vitamins A and E reduce hy droperoxide-initiated chemiluminescence and myocardial cell damage dur ing ischemia-reperfusion in the rabbit.