The Influence of Hyperglycemia on the Extent of Focal Cerebral Ischemia

ABSTRACT

The present study was undertaken to investigate the influence of hyperglycemia on focal cerebral ischemia in view of morphometric assay and neuropathological examination. Forty Sprague-Dawley rats were divided into two groups of 20 each. Rat MCA occlusion model was used for induction of focal ischemia. Hyperglycemia(20 rats, mean(SEM plasma glucose concentration 378(97.6 mg/dl) was established 30 minutes before MCA occlusion by intraperitoneal injection of 50% dextrose in water;the control group(20 rats, mean(SEM plasma glucose concentration 121(24.9 mg/dl) received normal saline only. Twenty-four hours after MCA occlusion neutral red staining and perfusion fixation was performed and ischemic area were measured using computerized image analysis on cortical surface and coronal cut surface. There was no significant difference on coronal cut surface, but on cortical surface showed increase of non-stained area(infarct core) and decrease of lightly stained area(transitional zone) in hyperglycemic rats(p<0.05) and the sum of two area was not different between two groups. Pathological findings were evaluated under light microscopy, in which the field scanning was carried out from the midline by 0.5 mm interval at cortical and basal ganglia level. There showed no significant difference at basal ganglia level, but at cortical level ischemic transitional zone was decreased in hyperglycemic rats(p<0.05). We conclude that hyperglycemia may worsen the brain from severe, focal ischemic neuronal damage.