Experimental Cerebral Infarction in the Dog : Scanning Electron Microscopy with Vascular Endocasts of the Microvessels in the Ischemic Brain

Large-sized infarctions of the cerebral hemisphere (LSICH) were expreimentally induced in 17 dogs by injecting two silicone cylinders through the right cervical internal carotid artery. The LSICH models were perfused with heparinized saline and fixed with 1.5% glutaraldehyde solution through the contralateral carotid artery. Then 24 hours after the embolization, Mercox(R) CL-2B and CL-2R were injected manually. The brains were immediately removed, and specimens were obtained from the basal ganglia and the ectosylvian cortex. Disruptions of the degenerated arterioles with numerous erythrocytes and Mercox were observed in the area of massive hemorrhagic infarct in the basal ganglia. On the other hand, disruptions of degenerated venules with a few erythrocytes and Mercox around the vessels were observed in the petechial hemorrhagic infarct in the corticomedullary junction area. Dilatation of the pervascular space of the microvessels and vacuolation of the neuropiles were related to the severity of the vasogenic edema. Microvessels were narrowed and decreased in flexibility in severe vasogenic edema. Some arterioles ran parallel and branched convergently. It was suggested that changes in the microvascular structure were caused by disturbance of the autoregulation of the cerebral microcirculation