AN EXPERIMENTAL-MODEL OF CEREBRAL MICROISCHEMIA IN RABBITS

Multiinfarct dementia is the second most common form of dementia in th e elderly. An animal model of microischemia may provide information ab out the pathophysiology relevant when searching for prevention or trea tment of microinfarctions in humans. The purpose of the present study was to develop an experimental model useful for studying discrete micr oischemic foci. In order to achieve single cerebral microischemic foci plastic beads with diameters of about 100 mu m were injected into the left heart ventricle of anesthetized rabbits. 2-Deoxy-[C-14]glucose ( 2-DG) and autoradiography were used to detect regions with disturbed m etabolism. The tissue sections were inspected for impacted beads. Foci with markedly increased 2-DG accumulation and with diameters of about 1 mm were detected in all parts of the brain, indicating hypoxic regi ons with enhanced glycolysis. In some foci, located mainly in the basa l ganglia, a central dip in the 2-DG profile was seen, suggesting poor glucose supply to the central ischemic region. The ratio foci/beads w as about 1 in the brain stem (diencephalon included) and about 0.5 in the cortex. Twenty-four hours after embolization, infarctions, mainly in the deeper brain regions, were seen. There were still foci with inc reased 2-DG; uptake, which were mainly located in the cortex. The resu lts suggest that microemboli reaching the deeper brain regions give ri se to metabolic disturbances more often than emboli reaching the corte x and that the ischemic foci in deeper brain regions are more prone to develop further into infarctions. (C) 1996 Academic Press, Inc.