Immunohistochemical investigation of cerebral ischemia after middle cerebral artery occlusion in gerbils.

Progression and recovery of ischemic and postischemic damage after occlusion of the middle cerebral artery and subsequent reperfusion were investigated in the gerbil. This study was performed by immunohistochemical reaction testing for tubulin and creatine kinase BB-isoenzyme to visualize the neuronal structure and by immunohistochemical reaction testing for astroprotein (an astrocyte-specific protein) to visualize reactive astrocytes. The earliest ischemic lesion became visible in the frontoparietal cortex after 7 minutes of ischemia as a laminar loss of the reaction for tubulin involving the neuropil, neuronal perikarya, and dendrites. The earliest lesion in the caudoputamen evolved after 30 minutes of ischemia. After reestablishment of cerebral circulation, the immunohistochemical ischemic lesions in the neuronal structure disappeared if the ischemic period was 10 minutes or less and partially disappeared even after ischemia for 15 minutes in the cerebral cortex, while the postischemic lesion in the caudoputamen disappeared even after ischemia for 15 minutes. Reactive astrocytes were detected in the cerebral cortex and caudoputamen as early as 24 hours after reperfusion, both in the areas with and without the neuronal lesions. No lesion was identified in the hippocampus or thalamus. This experimental model is suitable for investigation of rapidly progressive regional ischemia in the cerebral cortex and for comparison with other regional or global cerebral ischemia in the gerbil or other animal species.