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 ''pressing 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. These results demonstrate that reversible vascular occlusion in the normal, Sprague-Dawley rat results in consistent amounts of tissue infarction. This approach represents an attractive model system for studying the pathophysiological effects of transient, focal ischemia and for testing the effects of putative, therapeutic strategies.