EFFECTS OF ALPHA-TOCOPHEROL ON LIPID-PEROXIDATION AND MITOCHONDRIAL REDUCTION OF TETRAPHENYL TETRAZOLIUM IN THE RAT-BRAIN

The antioxidant effect of alpha-tocopherol was assessed in a model of ischemia-reperfusion in the rat brain. In this model, permanent ischemia of the cortical branches of the middle cerebral artery was combined with bilateral occlusion of the common carotid arteries for 1 h and restoration of circulation for a period of 2 h. Lipid peroxidation and mitochondrial reduction of tetraphenyl tetrazolium (TPT) were determined in both untreated and d-alpha-tocopherol treated rats. Ferrous sulfate and ascorbic acid (FeAs) were used to induce lipid peroxidation via the formation of hydroxyl anions. Malondialdehyde (MDA) increased in the ischemia-reperfusion areas (+101%), but FeAs-induced MDA did not vary in the area of permanent ischemia. Brain tissue undergoing ischemia-reperfusion was about 50% less sensitive to the antioxidant effect of ascorbic acid. The reduction of TPT showed 52% mitochondrial damage in the area of ischemia-reperfusion, whereas mitochondrial activity in the area of permanent ischemia was 177 times lower as compared to controls. d-alpha-tocopherol caused a 40% inhibition of MDA production and 16.5% and 21.5% decrease in mitochondrial activity in the areas of ischemia-reperfusion and permanent ischemia, respectively.