초점성 뇌경색에서 선택적 뇌저온 치료법의 허혈성 뇌파괴와 뇌부종에 대한 치료효과 = Therapeutic Effect of Postischemic Selective Brain Cooling on Ischemic Brain damage and Edema in Focal cerebral Infarction

다국어 초록 (Multilingual Abstract)

The present study investigates the effect of temporary selective brain cooling(S8C) on ischemic brain damage and edema on permanent middle cerebral artery(MCA) occlusion in the rat. Eighteen adult male Sprague-Dawley rats weighing 300-4OOg were used under halothane anesthesia. The brain temperature was monitored in the left caudate nucleus through a burr hole in the middle of the left coronary suture. All animals underwent left MCA occlusion via subtemporal approach During the surgery, the physiological variables including mean arterial blood pressure were monitored continuously. Three groups of animals were studied : group 1. normothermic brain themperature control(n=6) ; group 2. brain cooling for 30 min(n=6) ; and group 3. brain cooling for 60 min(n=6) in all groups. rectal temperature was maintaind 36.5℃ -37℃, and in groups 2 and 3, brain temperature was lowered to less than 34℃ by active cooling. 15 min following MCA occlusion. After the brain cooling treatment, anesthesia ws discontinued, and the animals were returned to the cage. Twenty-four hours following MCA occlusion, the rats were sacrificed. The volume of ischemic damage and edema was obtained by frozen section technique. There were no significant differences in all physiological parameters between normothmic and hypothermic animals, except the brain temperature. Postischemic SBC for either 30 or 60 min significantly reduced the volume of infarction in the csrebral hemisphrere by 14%(p<0.05) or by 27%(p<0.01) respectively, and also attenuatd neurologic deficits observed at 24 hour postocclusion. However. the volume of ischemic brain edema was not significantly reduced, and the ratio of volume of brain edema/infarction increased significantly in groups 2(p<0.05) and 3(p<0. 05) compared with group 1. The present study demonstrates that postischemic temporary SBC can attenuate hemispheric infarction in a permanent focal cerebral sichemia model in the rat. However, ischemic brain edema appears not to be attenuated at all. The mechanisms of hypothermic protection and its clinical application are discussed.