Combined Effect of Hypothermia and Hyperglycemia onTransient Focal Cerebral Ischemia of the Rat

J Korean Neurol Assoc > Volume 18(6); 2000 > Article

Journal of the Korean Neurological Association 2000;18(6): 748-753.

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강미자*‡·, 구자성*·윤병우*†·노재규*†

서울대학교 의과대학 신경과학교실*,서울대학교 의학연구원 신경과학 연구소†,연변대학교 의학원 부속병원 신경과‡

Combined Effect of Hypothermia and Hyperglycemia onTransient Focal Cerebral Ischemia of the Rat

Mei-Zi Jiang, M.D.*‡, Ja-Seong Koo, M.D.*, Byung-Woo Yoon, M.D.*†, Jae-Kyu Roh, M.D.*†

Department of Neurology, Seoul National University College of Medicine*Neuroscience Research Institute in Medical Research Center, Seoul National University

Abstract

Background : In experimental cerebral ischemia, hypothermia protects the brain, while hyperglycemia aggravates ischemic damage. Clinical studies have also reported worse outcomes in ischemic stroke patients with hyperglycemia or fever and improved outcomes with hypothermic therapy. However, it is not well known what will happen if these oppo-site effects exist together. Methods : Sixty male Sprague-Dawley rats were used. Focal cerebral ischemia was induced for 2 hours by an intraluminal thread followed by reperfusion for 4 hours. Rats were divided into 4 groups; 1) normo-glycemic normothermic (NGNT), 2) normoglycemic hypothermic (low temperature) (NGLT), 3) hyperglycemic nor-mothermic (HGNT), and 4) hyperglycemic hypothermic (HGLT) groups (n=15 for each group). Hyperglycemia wasmade by intraperitoneal injection of streptozotocin (60 mg/kg) 3 days before ischemia. The body temperature was main-tained at 37±1 ℃in normothermic animals, while lowered at 32±1 ℃in hypothermic animals during the ischemic peri-od. Following reperfusion, 2-mm thick coronal slices were obtained and stained by triphenyltetrazolium chloride. The infarct volume was measured using an image analyzer. Results : Mean glucose levels (mean±SD in mg/dl) were 77.9±9.3 in NGNT, 77.7±11.5 in NGLT, 311.0±69.2 in HGNT, and 355.3±57.7 in HGLT. Mean infarct volumes (mean±SD in mm 3) were 168.2±44.2 in NGNT, 66.2±24.2 in NGLT, 417.6±123.2 in HGNT, and 337.2±89.3 in HGLT. The protective effect of hypothermia was less evident in hyperglycemic rats and the aggravating effect of hyper-glycemia was more evident in hypothermic rats. Infarct volume of HGLT was 2-fold bigger than that of NGNT (p<0.05). Conclusions : Our results suggest that the detrimental effect of hyperglycemia may override the protective effect of hypothermia in transient focal cerebral ischemia. J Korean Neurol Assoc 18(6):748~753, 2000Key Words : Focal Cerebral Ischemia, Hyperglycemia, Hypothermia