[Effect of antioxidants on the status of the antioxidative system in cerebral ischemia and reperfusion injury].

Protective effects of ionol, o-benzoquinone-2 and ascorbic acid, their influence on the activity of antioxidative enzymes, the level of diene conjugates (DC) and of recovered glutathione in the mitochondrial fraction in the case of ischemic and reperfusion injury of the brain have been investigated. An increase in the activity of the antioxidative system enzymes during the post-ischemic period induced probably by the accumulated products of lipid peroxidation is shown: glutathione peroxidase (EC 1.11.1.9)--by 159%, glutathione reductase (EC 1.6.4.2)--by 26%, catalase (EC 1.11.1.6)--by 79%. This effect was not observed after introduction of antioxidants lowering the DC-level. It is concluded that antihypoxic action of the investigated antioxidants providing the survival of animals not only after the 5 min total circulatory ischemia but also after the 15 min one is caused by their antiradical properties and is not connected with stimulation of activity of enzymes supporting peroxidative homeostasis.