Karibe H, Zarow G J, Graham S H, Weinstein P R
Department of Neurological Surgery, School of Medicine, University of California, San Francisco.
J Cereb Blood Flow Metab. 1994 Jul;14(4):620-7. doi: 10.1038/jcbfm.1994.77.
Mild to moderate hypothermia (30-33 degrees C) reduces brain injury after brief (< 2-h) periods of focal ischemia, but its effectiveness in prolonged temporary ischemia is not fully understood. Thirty-two Sprague-Dawley rats anesthetized with 1.5% isoflurane underwent 3 h of middle cerebral artery occlusion under hypothermic (33 degrees C) or normothermic (37 degrees C) conditions followed by 3 or 21 h of reperfusion under normothermic conditions (n = 8/group). Laser-Doppler estimates of cortical blood flow showed that intraischemic hypothermia reduced both postischemic hyperperfusion (p < or = 0.01) and postischemic delayed hypoperfusion (p < or = 0.01). Hypothermia reduced the extent of blood-brain barrier (BBB) disruption as estimated from the extravasation of Evans blue dye at 6 h after the onset of ischemia (p < or = 0.01). Hypothermia also reduced the volume of both brain edema (p < or = 0.01) and neuronal damage (p < or = 0.01) as estimated from Nissl-stained slides at both 6 and 24 h after the onset of ischemia. These results demonstrate that mild intraischemic hypothermia reduces tissue injury after prolonged temporary ischemia, possibly by attenuating postischemic blood flow disturbances and by reducing vasogenic edema resulting from BBB disruption.
轻至中度低温（30 - 33摄氏度）可减轻短暂（<2小时）局灶性缺血后的脑损伤，但其在长时间短暂性缺血中的有效性尚未完全明确。32只使用1.5%异氟烷麻醉的斯普拉格-道利大鼠在低温（33摄氏度）或常温（37摄氏度）条件下接受3小时大脑中动脉闭塞，随后在常温条件下再灌注3或21小时（每组n = 8）。激光多普勒血流仪对皮质血流的评估显示，缺血期低温可减轻缺血后高灌注（p≤0.01）和缺血后延迟性低灌注（p≤0.01）。低温降低了血脑屏障（BBB）的破坏程度，这是根据缺血开始后6小时伊文思蓝染料的外渗情况评估得出的（p≤0.01）。低温还降低了脑水肿体积（p≤0.01）和神经元损伤程度（p≤0.01），这是根据缺血开始后6小时和24小时的尼氏染色切片评估得出的。这些结果表明，轻度缺血期低温可减轻长时间短暂性缺血后的组织损伤，可能是通过减轻缺血后血流紊乱以及减少血脑屏障破坏导致的血管源性水肿来实现的。
