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 reducing oxyradical effects and myocardial damage after ischemia - reperfusion in the rabbit heart. Oxyradical effects were indirectly assessed by hydroperoxide initiated chemiluminescence and myocardial damage was evaluated by qualitative and quantitative electron microscopy. Left anterior coronary artery was ligated in control and vitamin-treated rabbits for 30 min and then reperfused for 10 min. Rabbits were pretreated with 150 mg vitamin E and 60000 IU vitamin A 24 h before surgery, After 10 min of reperfusion full-thickness needle samples were obtained from five different myocardial areas (three ventricular and two septal areas) and used for the determination of hydroperoxide-initiated chemiluminescence and ultrastructural damage. In the control group, hydroperoxide-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 was 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 ischemia-reperfused areas showed extensive edema, margination of nuclear chromatin and swollen mitochondria with disrupted cristae including rupture of the inner and outer mitochondrial membranes. Assessment of mitochondrial damage in electron micrographs by stereological counting and grading indicated 77% of damaged mitochondria. These hearts displayed the early signs of irreversible damage and infarction. Rabbits pretreated with vitamins A and E showed a 18% of damaged mitochondria in the same areas (p < 0.001) and relative preservation of myocyte subcellular structures. The results indicated that vitamins A and E reduce hydroperoxide-initiated chemiluminescence and myocardial cell damage during ischemia-reperfusion in the rabbit.