不同程度颈动脉狭窄对大鼠脑缺血再灌注损伤的影响

Prove into the cerebral ischemia-reperfusion injury and the possible mechanisms in the different degrees of carotid artery stenosis in rats

目的:通过观察不同程度颈动脉狭窄大鼠脑缺血再灌注后缺血半暗区病理、神经细胞凋亡和XIAP、Smac蛋白表达变化,探讨颈动脉狭窄对脑缺血再灌注损伤的影响及机制。方法:通过针控线栓法制备不同程度颈动脉狭窄大鼠模型,并随机分为对照组、轻度狭窄组、中度狭窄组、重度狭窄组,30 d后行缺血再灌注处理,分别于缺血再灌注12 h和24 h采集标本,采用HE染色法观察脑组织病理改变,TUNEL法检测缺血半暗区细胞凋亡,RT-qPCR法检测XIAP和Smac蛋白表达。结果:缺血再灌注12 h和24 h,轻度狭窄组、中度狭窄组和重度狭窄组较对照组大鼠梗死侧脑组织疏松、细胞结构紊乱、细胞空泡样变、细胞核裂解;缺血再灌注24h神经细胞凋亡显著增加;中度狭窄组和重度狭窄组较对照组大鼠XIAP和Smac蛋白表达均显著增高。结论:颈动脉狭窄可加重脑缺血再灌注损伤,且颈动脉狭窄程度越重、再灌注时间越长导致的损伤也越严重,其机制与激活XIAP/Smac信号通路诱导神经细胞凋亡有关。

Objective To investigate the effect and mechanisms of carotid artery stenosis on cerebral ischemia-reperfusion injury by observing the pathological changes of ischemic penumbra,neuronal apoptosis and XIAP,SMAC proteins expressions in rats with different degrees of carotid artery stenosis.Methods The rats models of different degrees of carotid artery stenosis were established by needle controlled thread occlusion method and randomly divided into control group,mild stenosis group,moderate stenosis group and severe stenosis group.The rats were treated with ischemia-reperfusion 30 days later,respectively in the 12 h and 24 h after reperfusion,the pathological changes of brain tissues were observed by HE staining,apoptosis in ischemic penumbra were detected by TUNEL method,and the expressions of XIAP and Smac proteins were detected by RT-qPCR.Results Compared with the control group,mild stenosis group,moderate stenosis group and severe stenosis group showed more loose brain tissue,disordered cell structure,cell vacuolation,nuclear fragmentation and neuronal apoptosis(24 h after ischemia-reperfusion).At 12 h and 24 h after ischemia-reperfusion,the expressions of XIAP and Smac proteins in moderate stenosis group and severe stenosis group were significantly higher than that in control group.Conclusion Carotid artery stenosis can aggravate cerebral ischemia-reperfusion injury,and the more severe the degree of carotid artery stenosis and the longer the reperfusion time,the more serious the injury is.The mechanism is related to the activation of XIAP/SMAC signaling pathway to induce neuronal apoptosis.