CORTICAL INFARCT VOLUME IS DEPENDENT ON THE ISCHEMIC REDUCTION OF PERIFOCAL CEREBRAL BLOOD-FLOW IN A 3-VESSEL INTRALUMINAL MCA OCCLUSION REPERFUSION MODEL IN THE RAT/

Occlusion of the middle cerebral artery (MCA) causes a reduction of ce rebral blood flow (CBF), which shows a progressive decrease from the p eriphery to the core of the MCA territory. The severity of ischemia is dependent on the duration of the ischemic episode and degree of CBF r eduction. Fixing the ischemic episode to 1 h, we have examined whether or not cortical infarct size was related to the degree of CBF reducti on in a perifocal cortical area in rats. One-hour intraluminal MCA occ lusion accompanied with bilateral common carotid artery (CCA) occlusio n (three-vessel occlusion/reperfusion model) was carried out in Spragu e-Dawley rats and CBF was monitored with laser-Doppler flowmetry in th e fronto-parietal cortex, an area which is perifocal to the core of th e MCA territory. Finally, infarct size was measured 7 days later and w as related to the corresponding CBF decrease. Sequential ipsilateral C CA, MCA and contralateral CCA occlusions produced reductions of CBF to 96%, 52% and 33% of baseline, respectively. Cortical infarct volume w as found to be dependent on the corresponding reduction of perifocal c ortical CBF during the ischemic episode. These results show that the r eduction of CBF in the periphery of the MCA territory during 1-h focal ischemia determines infarct size in a three-vessel occlusion/reperfus ion model.