大鼠脑缺血再灌注后DNA单链断裂与XRCC1的表达变化

Changes of XRCC1 expression and DNA single-strand break following local cerebral ischemia/reperfusion in rats

目的 观察脑缺血再灌注损伤中XRCC1表达、DNA单链断裂 ,探索它们的关系。方法 应用线栓法建立大鼠局灶性脑缺血再灌注模型 ;免疫组化检测XRCC1蛋白表达 ;单细胞凝胶电泳检测细胞DNA单链断裂。结果 基底节XRCC1在缺血再灌注 10min后即出现降低 ,1h后整个大脑中动脉供血区XRCC1进一步下降 ,一直持续到 48h。单细胞凝胶电泳显示缺血再灌注 10min基底节区出现DNA单链断裂 ,12h达到高峰 ,48h仍有DNA单链断裂。结论 在脑缺血再灌注中 ,XRCC1早期降低是DNA单链断裂无法修复的机制之一。

Objective To investigate the expression of x ray repair cross complementing group 1 (XRCC1) and DNA single strand break (DNA ssb) and their relation with cerebral ischemia/reperfusion in rats. Methods Adult Wistar rats were subjected to focal cerebral ischemia for 2 h, and then reperfused for 10 min and 1, 4, 12, 24, and 48 h. XRCC1 protein expression was analyzed by immunohistochemistry. DNA ssb was evaluated by comet assay. Results The XRCC1 level decreased markedly in the basal ganglia at 10 min, further decreased in the entire middle cerebral artery territory at 1 h, and remained decreasing until 48 h. DNA ssb appeared at 10 min after ischemia/reperfuion and peaked the value at 12 h after ischemia/reperfusion. Conclusion Early decrease of XRCC1 is one of the mechanisms in DNA ssb.