大鼠脑缺血再灌注区转录修复偶联因子表达与神经元DNA损伤的研究

CSB/ERCC6 expression and neuronal DNA damage in area of cerebral ischemia-reperfusion of rats

目的 探讨大鼠脑缺血再灌注后缺血区不同时相转录修复偶联因子 (CSB/ERCC6 )表达对神经元DNA损伤的作用。方法 Wistar大鼠 5 9只分为对照组、假手术组和实验组 ,实验组又分为缺血 2h再灌注 12、2 4、48、72、12 0、16 8h组 ,分别用原位杂交和原位末端标记 (TUNEL)方法检测大脑中动脉阻塞 2h再灌注不同时相点局部脑组织CSB/ERCC6mRNA表达及神经元DNA损伤的情况。结果 局部缺血区域神经元DNA损伤于再灌注 12h开始出现 ,2 4h最为严重 ,72h开始减轻。大鼠脑缺血再灌注后 48h ,局部脑组织CSB/ERCC6mRNA表达开始升高 ,于再灌注 72h达到峰值 ,持续至 12 0h仍保持较高水平表达。结论 脑缺血再灌注后表达增高的CSB/ERCC6mRNA与局部缺血区域神经元DNA损伤密切相关 ,CSB/ERCC6mRNA作为转录修复偶联因子 ,可能调节了神经元DNA损伤后的自身修复能力。

Objective To investigate the transcription-coupled repair factor CSB/ERCC6 expression and neuronal DNA damage in ischemic area after cerebral ischemia-reperfusion in rats.Methods Fifty-nine male Wistar rats were randomly divided into 3 groups:control group,sham operation group and cerebral ischemia-reperfusion group(reperfusion for 12,24,48,72,120,168 hours after ischemia).In situ hybridization and TUNEL staining were used respectively to evaluate CSB/ERCC6 mRNA expression and neuronal DNA damage in focal brain tissue after various durations of reperfusion following middle cerebral artery occlusion(MCAO) for 2 hours in rats.Results Neuronal DNA damage appeared in ischemic tissue at 12 hours of reperfusion,peaked at 24 h,started to decrease at 72 h.The expression of CSB/ERCC6 mRNA started to increase after reperfusion for 48 hours,peaked after reperfusion for 72 hours,and continued for 120 hours.Conclusion The increased expression of CSB/ERCC6 mRNA after cerebral ischemia-reperfusion is significantly correlated with the degree of neuronal DNA damage in focal ischemic brain tissue.CSB/ERCC6 mRNA,a transcription-coupled repair factor,may contribute to neuronal DNA repair.