MODIFICATION OF VITAMIN-E DURING ISCHEMIA-REPERFUSION IN RAT RETINA

Purpose. To determine the variations of vitamin E in rat retinas after transient ischemia and reperfusion. Methods. Male Wistar rats 11 to 12 weeks of age were used in all experiments. Ischemia was induced by ligation of the optic nerve and vessels, then reperfusion was obtained by removing the ligature. Retinas were dissected, and vitamin E was analyzed by a modified high-performance liquid chromatography assay. Results. There was an insignificant rise in vitamin E during ischemia and a dramatic decrease after reperfusion. No changes were dependent on the period of ischemia (30, 60, or 90 minutes) or reperfusion (15 or 120 minutes). Conclusion. Vitamin E decreased only in the reperfused groups, demonstrating a depletion of defenses against free radical production occurring during reperfusion. Vitamin E changes may represent an indirect measure of lipoperoxidation during ischemia-reperfusion and, thus, a potential parameter to evaluate drugs in vitro.