A CHANGE OF P-SELECTIN IMMUNOREACTIVITY IN RAT-BRAIN AFTER TRANSIENT AND PERMANENT MIDDLE CEREBRAL-ARTERY OCCLUSION

Although the role of an adhesion molecule such as P-selectin may be im portant in the pathogenesis of stroke, temporal, spacial, and cellular profiles of the expression of such a protein has not been fully studi ed in the case of the middle cerebral artery (MCA) occlusion and reper fusion in rat brain. Change in expression of immunoreactive P-selectin was examined in rat brain after transient MCA occlusion (MCAO) in com parison to that of permanent occlusion with an anti-P-selectin monoclo nal antibody. Western blot analyses were performed to ensure the selec tive detection of immunoreactive P-selectin protein with the monoclona l antibody using brain homogenates before and after MCAO. Temporal, sp acial, and cellular changes of P-selectin expressions were evaluated w ith rat brain sections at 2, 8 h, I and 3 days of permanent MCAO, and at 2, 8 h, 1, 3 and 7 days of reperfusion after 7 h of transient MCAO. Western blot showed a single band with a molecular weight of 140 kDa for both cases with permanent occlusion and reperfusion. P-selectin im munoreactivity was not normally present in rat brain sections. However , it was expressed mainly in the post-capillary venules of the cerebra l cortex and caudate in the MCA territory with a peak at 2-8 h after p ermanent occlusion and at 8 h to I day after the reperfusion. The expr ession was diminished by I day of permanent occlusion and 3 days of re perfusion. The maximum staining in the case of permanent MCAO was stro nger than the case with reperfusion. However, spacial distribution of the staining was similar in the cerebral cortex and caudate between th e cases with permanent or transient MCAO. These results suggest a diff erent temporal but similar spacial and cellular expression of P-select in immunoreactivity between permanent occlusion and reperfusion of MCA in rat brain.