INFARCT VOLUME VARIES WITH RAT STRAIN AND VENDOR IN FOCAL CEREBRAL-ISCHEMIA INDUCED BY TRANSCRANIAL MIDDLE CEREBRAL-ARTERY OCCLUSION

We recently reported that the outcome of focal cerebral ischemia induc ed by intraluminal middle cerebral artery occlusion may differ dependi ng upon a rat's strain and/or vendor. Sprague-Dawley rats originating from Taconic Laboratories and Charles River Laboratories had infarct v olumes several fold larger than Sprague-Dawley rats originating from S imonsen Laboratories. The present study sought to determine whether th ese differences were restricted to an intraluminal technique or whethe r strain and vendor dependent differences will also exist in rats subj ected to a transcranial method of focal cerebral ischemia. Accordingly , we permanently coagulated the middle cerebral artery via a transcran ial approach in Sprague-Dawley rats originating from Simonsen Laborato ries and Taconic Laboratories and in Simonsen Laboratories Fischer-344 rats. The cortical infarct volume significantly differed in the follo wing order: Simonsen Laboratories Sprague-Dawley rats < Simonsen Labor atories Fischer-344 rats < Taconic Laboratories Sprague-Dawley rats. T he subcortical infarct volume differed statistically in the following order: Simonsen Laboratories Sprague-Dawley rats < Taconic Laboratorie s Sprague-Dawley rats < Simonsen Laboratories Fischer-344 rats. These results along with our previous findings demonstrate that strain and v endor differences in the outcome of focal cerebral ischemia are indepe ndent of the technique applied.