Neuroprotective Effects of Selective Brain Hypothermia (SBH) on Permanent Focal Cerebral Ischemia in Rats

Abstract

This study was aimed at examining whether postischemic transient hypothermia is neuroprotective against permanent cerebral ischemia in rats. Male Sprague-Dawley rats were subjected to a left proximal middle cerebral artery occlusion and assigned into three groups. In the hypothermic group, rats received selective brain hypothermia and rewarmed. In the control and sham groups, the rats were maintained at normothermia. At 6–168 h after ischemia, the brains were removed and stained with hematoxylin-eosin in order to measure infarction size. Data obtained from this study were statistically analyzed. There were no significant differences in physiological parameters except for the temperature. The hypothermia significantly reduced the hemispheric infarction, and acted neuroprotectively in both the cortex and the basal ganglia. The subsequent remarks on methodology are addressed to evaluate the usefulness of the hypothermia. Muscle temperature was reduced to 29°C, which is concordant with the 31°C of the basal ganglia temperature. The keystone during hypothermia is the maintenance of the mean arterial blood pressure above 90 mmHg. We conclude that postischemic transient hypothermia is neuroprotective in the present model of ischemia.