The role of strain/vendor differences on the outcome of focal ischemia induced by intraluminal middle cerebral artery occlusion in the rat

Abstract

This study investigated the role of strain and vendor differences on the outcome of focal cerebral ischemia in the rat induced by occlusion of the middle cerebral artery by an intraluminal thread. The cortical infarct volumes (Mean +/- S.E.M.) were: 14.2 +/- 6.2 mm3 in Simonsen Laboratories Sprague-Dawley rats; 84.0 +/- 22.9 mm3 in Simonsen Laboratories Wistar rats; 223.3 +/- 23.6 mm3 in Taconic Laboratories Sprague-Dawley rats; and 239.5 +/- 30.7 mm3 in Charles River Laboratories Sprague-Dawley rats. Middle cerebral artery occlusion combined with bilateral common carotid artery occlusion for 60 min increased cortical infarct volumes to: 113.0 +/- 18.8 mm3; 152.4 +/- 21.1 mm3; 227.8 +/- 19.3 mm3; and 248.4 +/- 24.0 mm3, respectively. To control the effect of blood pressure as a variable contributing to the outcome of ischemia, additional experiments where performed in which the blood pressure in Simonsen Laboratories Sprague-Dawley rats was lowered to the level of the blood pressure in Taconic Laboratories Sprague-Dawley rats. Although this manipulation increased the cortical infarct volumes in Simonsen Laboratories Sprague-Dawley rats, the volumes were still less than those in Taconic Laboratories Sprague-Dawley rats. The results of the present study indicate that the outcome of ischemia in the intraluminal thread model may dramatically differ depending on the strain and vendor of animal used.