The changes of infarcted area and regional cerebral blood flow in rats subjected to reversible middle cerebral artery occlusion *
The purpose of this study was to evaluate time dependent changes in rCBF (regional cerebral blood flow) and an infarcted area after temporal middle cerebral artery occlusion in rats. The right middle cerebral artery and common carotid artery were occluded for 1, 2 and 26 hrs using the intraluminal filament method in permanent occlusion groups. Reperl'usion group rats were occluded for 1, 1.5, 2 and 3 hrs, and were sacrificed 26 hrs after onset of ischemia. Infarction was observed in the ischemic core and the perifocal regions in the 26 hr permanent ischemia group. In the reperfusion groups, the infarcted rate increased rapidly when the ischemic time exceeded 1.5 hrs. The infarcted rate of reperfusion group after 3 hrs of ischemia became worse than that of the 26 hr permanent ischemia group. The rCBF in the ischemic core and the perifocal regions was reduced time-dependenlly, but that in the exofocal regions (regions not perfused by the middle cerebral artery but which have a neuronal connection with the ischemic core) increased during permanent ischemia. In the reperfusion groups, rCBF in the ischemic core and the perifocal regions changed variably depending on whether the ischemic time exceeded 1.5 hrs or was within 1.5 hrs. In the exofocal regions, increase in the rCBF was only seen in the SNR (substantia nigra ). The findings in this experimental model suggest that reperfusion done within 1.5 hrs is beneficial to the ischemically injured brain, but that deterioration will have already occurred if reperfusion is done after 3 hrs. In addition, it was suggested that rCBF in the exofocal regions was changed transneuronally, depending on ischemic damage of the ischemic core. However, the reaction of the rCBF in the exofocal regions differed from each area. (Accepted on August 19, 1999) Kawasaki lgakkaishi 25(3): 181-192, 1999
