大鼠局灶性脑缺血耐受模型的建立与评价

Establishment and Evaluation of Focal Cerebral Ischemic Tolerance Model

目的 建立大鼠大脑中动脉局灶性缺血再灌注及缺血耐受模型,探讨该模型的应用价值.方法 将88只Wistar大鼠随机分成假手术组（8只）、假手术＋再缺血组（NIP,40只）、缺血预处理＋再缺血组（IP,40只）,后两组再随机分成5个亚组.线栓法阻塞大脑中动脉（MCA）完成局灶性缺血预处理（缺血预处理10min）,分别在缺血预处理后1,3,7,14,21d进行再次缺血2h再灌注22h后处死.模型建立后通过神经功能评分、TTC染色测定脑梗死体积及细胞凋亡等对模型进行评估.结果 ①组间比较：与NIP组相比,IP组中的1,3,7d亚组神经功能评分及脑梗死体积明显降低（P＜0.05或P＜0.01）;IP组中的1,3,7,14d亚组凋亡细胞计数明显减少（P＜0.05）.②组内比较：IP组各亚组间神经功能评分差异无显著性;IP组1,3,7d亚组梗死体积较14,21d亚组明显减小,其中以3d亚组梗死体积减小最为明显（P＜0.05）;IP组以3,7d亚组平均凋亡细胞计数较其他亚组明显减少 （P＜0.05）.结论 线栓法制备脑缺血耐受模型切实可行,具有一定的应用价值.

Objective To establish and evaluate cerebral ischemic tolerance model induced by focal ischemic preconditioning in rats. Methods Eighty-eight male Wistar rats were randomly divided into three groups ： sham operation group（ n = 8 ） , non-ischemic preconditioning（ NIP, n = 40 ） group, and ischemic preconditioning （ IP, n = 40 ） group. For isehemic preconditioning, the rats were given middle cerebral artery occlusion（MCAO） for 10 minutes. In the IP group,rat models of pre-ischemia-reperfusion-ischemia-reperfusion were established by MCAO using the twice suture method. In the NIP group, pre-ischemia was replaced by sham operation. Subsequently, the IP and NIP group were equally divided into five subgroups, that was 1- ,3-,7-, 14-, and 21-day subgroup. The rats in the sham operation group received the sham surgery two times. The models were evaluated through the following index ： neurologic deficit scores, infarct volume and nerve cell apoptosis. Results （1）Intergroup comparison：compared with the NIP group,neurologic deficit scores and infarct volume significantly decreased in the 1,3,7d subgroups of IP group（ P 〈0.05 ;P 〈0.01 ）. The number of apoptotic cells significantly decreased in the 1,3,7 and 14d subgroups of IP group （ P 〈 0.05 ）. （2）In the IP group, there was no significant difference in neurologie deficit scores among subgroups, infarct volume significantly decreased in the 1,3 ,Td subgroups（ P 〈0.05） , the number of apoptotic cells significantly decreased in the 3 ,Td subgroups（ P 〈 0. 05）. Conclusion The results showed that 10-minute pre-ischemia induces cerebral ischemic tolerance to a subsequent severe ischemic insult, the effect of which is still present after 7 days of reperfusion. It is practicable for preparation of a rat model of ischemic tolerance induced by focal ischemic preconditioning.