Abstract
The expression profiles of cyclooxygenase-2 (COX-2) mRNA following transient and permanent middle cerebral artery (MCA) occlusion were studied using in situ hybridization. COX-2 immunoreactivity was also evaluated in permanent MCA occlusion. COX-2 mRNA was induced prominently in the ischemic cortex at 4 h of reperfusion following 30 min of transient occlusion and persistently until 24 h of the reperfusion period. With 90 min of transient occlusion and permanent occlusion, it was induced over a widespread region of the cerebral cortex except the ischemic region, medial striatum and bilateral hippocampi. Immunohistochemical investigations revealed COX-2 immunoreactivity in the large neuronal cells of the cerebral cortex, granule cells and pyramidal cells in the hippocampi at 24 h of permanent occlusion. In this study, COX-2 was shown to be induced in the surrounding and remote ares of the ischemic region as well as in the ischemic region itself. These data suggest that persistent acceleration of arachidonic acid metabolism might be elicited even in areas remote from the ischemic region.
