Cerebral Blood Flow and Glucose Metabolism of the Ischemic Rim in Spontaneously Hypertensive Stroke-Prone Rats with Occlusion of the Middle Cerebral Artery

To determine acute postischemic metabolic changes of the ischemic rim under conditions of poor collateral circulation, we examined cerebral blood flow and glucose metabolism in the area of the brain around the ischemic tissue in 36 male spontaneously hypertensive stroke-prone rats (SHRSP) in the acute stage of focal ischemia. The right middle cerebral artery (MCA) was occluded dorsal to the rhinal fissure. Four hours after occlusion, local cerebral blood flow (LCBF), glucose content (LCGC), and glucose utilization (LCGU) were measured by quantitative autoradiographic techniques. The lumped constant was determined from the corresponding LCGC. LCBF showed a widespread and marked decrease in the cortex surrounding the ischemic core, in the thalamus, and in the medial portion of the striatum in the MCA-occluded hemisphere, while the lateral segment of the striatum showed an increase of 36%, compared with findings on the contralateral side. LCGC showed little regional variation, but there was an increase of 38% in the zone bordering the ischemic area. LCGU at the cortex surrounding the ischemic core and in the external capsule showed an increase of 55%. The cortex surrounding the ischemic core, the thalamus, and the lateral segment of the striatum in the MCA-occluded hemisphere showed significant decreases in LCGU. It has been speculated that a high accumulation of glucose reflects a demand for glucose for anaerobic glycolysis in the border areas and that such a demand is probably greater in cases of impaired oxygen delivery due to the presence of microcirculatory disturbances in the MCA-occluded SHRSP. The enhancement of glucose consumption may reflect anaerobic glycolysis. Because the hypermetabolic band was present in the cortex and the white matter, hypermetabolism of the white matter may be related to the glial cell.