大鼠脑局灶性预缺血对再次缺血的影响

目的研究不同时间单次缺血及重复缺血引起的脑组织病理变化。方法插线法阻塞大鼠大脑中动脉（ＭＣＡ）。单次缺血８、２８或９０ｍｉｎ，重复缺血８＋２８ｍｉｎ或２８＋９０ｍｉｎ。结果单次缺血组随缺血时间延长脑病变加重。８＋２８ｍｉｎ组ＭＣＡ供血区病变重于２８ｍｉｎ组；２８＋９０ｍｉｎ组ＭＣＡ供血区病变轻于９０ｍｉｎ组。结论不同时间的预缺血对再次缺血有导致积累性损伤或缺血耐受的双重效应。

Effects of focal pre-ischemia on subsequent ischemia in rat brain

Objective To investigate the effects of primary shortperiod ischemia on the subsequent ischemia in brain. Method Occlusion of the right middle cerebral artery were performed on Wistar rats by inserting suture into the internal carotid artery. In single oclussion gruops,the rats were subjected to MCA occlusion for 8,28,or 90min. And in repeated occlusion groups,8min or 28min ischemic preconditioning was followed by second 28min or 90min ischemia. Result In the single ischemic groups,the brain injury increased as ischemic time prolonged.The damage of 28min ischemia preceded by 8min. Ischemic pretreatment was more severe than that of single 28min ischemia. However,when the pretreatment was prolonged to 28min the injury of the second ischemia of 90min was less than that of single 90min ischemia. Conclusion The results indicate that ischemic preconditioning of different times may lead either to a cumulative injury or ischemic tolerance.