The Effects of Moderate Hypothermia on the Formation of Apoptosis in Transient F degrees Cal Cerebral Ischemia Model in Rats

Woo, Tae Jung; Baik, Seong Wan; Chung, Kyoo Sub; Kim, Inn Se; Kim, Hae Kyu; Kwon, Jae Young

Abstract

BACKGROUND: Delayed neuronal injury after cerebral ischemia came major neurologic complication after stroke or cardiac arrest. Apoptosis formation after ischemia may be one of a mechanism of delayed neuronal injury. This study was conducted to evaluate the effect of moderate hypothermia on apoptosis formation after one hour of middle cerebral artery degrees Cclusion in rats.
METHODS
Ten Sprague-Dawley rats (300 g) were freely fed till just before operation. Anesthesia was induced with 4 vol% isoflurane in oxygen and then maintained with 2 vol% isoflurane in oxygen. Middle cerebral artery degrees Cclusion (MCAO) was induced by intraluminal monofilament nylon with blunted tip. All rats were divided randomly into two groups. In group 1 (n=5), rectal temperature was maintained at 38 degrees C. In group 2 (n=5), rectal temperature was maintained at 32 degrees C. Rectal temperature was monitored during experiment. After 60 minutes of MCAO, intraluminal monofilament was removed and all rats were returned to cages. Brain were quickly removed and cerebral hemispheres were separated after 23 hours reperfusion. Apoptosis formation were counted with TUNEL stain.
RESULTS
In group 1, after 60 minutes of MCAO and 23 hours reperfusion, 51 3.6% of hipp degrees Campal neurons were TUNEL-positive stained apoptotic cells. In group 2, TUNEL-positve neurons were 26.1 6.5% and significantly less than those of group 1 (p<0.05).
CONCLUSIONS
Sixty minutes of MCAO and 23 hours reperfusion induce hipp degrees Campal neuronal apoptosis. Moderate hypothermia of 32 degrees C reduces apoptosis of hipp degrees Campal neurons after 60 minutes of MCAO and 23 hours reperfusion.