ISCHEMIC TOLERANCE AND LIPID-PEROXIDATION IN THE BRAIN

USING a modified method of focal ischemic preconditioning (FIP) follow ed by permanent middle cerebral artery occlusion (MCAO), we studied th e effects of ischemic tolerance on infarct volume. The FIP was achieve d by obstructing the blood flow into the MCA using miniature clamps at two points simultaneously. The first point was proximal to its origin and the second was where it intersects the middle cerebral vein. In r ats subjected to three short conditioning periods (3 x 3 min with 7 mi n reperfusion between occlusions), there were significant reductions i n the infarct volume in the cerebral cortex induced by the subsequent MCAO in FIP-treated rats compared with sham-operated controls. This ra pid FIP-induced ischemic tolerance to subsequent MCAO occurred within 1 day and lasted for 5 days. Tissue lipid peroxidation in the cortex w as significantly reduced for up to 2 days after FIP. In contrast, lipi d peroxidation increased rapidly after MCAO. A significant reduction i n this increase was observed in LIP-treated rats, suggesting a correla tion with the subsequent reduction in the infarct volume. Neuro Report 9: 2269-2272 (C) 1998 Rapid Science Ltd.