A reproducible model of reversible, focal, neocortical ischemia in Sprague-Dawley rat

A reproducible model of reversible, focal ischemia was developed for use with the normotensive, Sprague-Dawley rat. Blood flow to the left cerebral hemisphere was interrupted by occluding simultaneously the left middle cerebral artery and both carotid arteries (CCA). The arterial occlusion lasted for 1, 2 or 3 hours after which animals survived for 3 days. The volume of brain infarction was determined utilizing computer-assisted measurements of serial brain sections stained with triphenyltetrazolium. Tissue infarctions of variable size were observed following arterial occlusions which persisted 1 or 2 hours. In contrast, remarkably-consistent infarction size was obtained following a three hours period of occlusion. Tissue edema was also estimated by measuring the volumes of the two hemispheres and expressing these values as a ratio for each animal. The volume ratio was significantly greater in the 3 hour ischemic group, indicating the occurrence of edema in the infarcted hemisphere.