Three-vessel occlusion using a micro-clip for the proximal left middle cerebral artery produces a reliable neocortical infarct in rats.

We demonstrate a new three-vessel occlusion model of temporary focal ischemia in Sprague-Dawley rats (n=13). Under a surgical microscope, bilateral carotid arteries and the left middle cerebral artery (MCA) were occluded for 2 h using a snare for the neck and a micro-clip for the MCA. The reduction of regional cerebral blood flow (rCBF) monitored by laser Doppler flowmetry was 28% on average compared to the preischemic control value (100%) during ischemia. At that level of CBF reduction, there was no thrombus formation in the proximal MCA trunk, and a full recovery of rCBF was confirmed in the ischemic core within 5 min of reflow. Two days later, the cerebral infarct was limited to the neocortex, and the size and variability of the infarct are considered feasible for the assessment of any therapeutic challenge against the ischemic damage due to temporary focal ischemia in this model.