Focal cerebral ischemia.

Rodent models of focal cerebral ischemia have been extremely useful in elucidating pathomechanisms of human stroke. Most commonly, a monofilament is advanced through the internal carotid artery of rodents to occlude the origin of the middle cerebral artery thus leading to critical ischemia in the corresponding vascular territory. The filament can be removed after different occlusion times allowing reperfusion (transient middle cerebral artery occlusion (MCAO) model) or is left permanently within the internal carotid artery (permanent MCAO model) both mimicking clinical thromboembolic stroke in which the occluding clot may resolve spontaneously or after thrombolysis, or may persist. Overall, the occlusion time determines the extent of ischemic brain damage, but infarcts still grow during reperfusion, a process involving complex interactions between platelets, endothelial cells, immune cells, and the coagulation system.