摘要
目的 探讨短暂性前脑缺血后大鼠海马NR2A和NR2BmRNA的表达变化及其与海马缺血性细胞凋亡的关系。方法 四动脉阻断法建立脑缺血再灌注动物模型、原位杂交、TUNEL染色和图像分析与统计处理。 结果①缺血后 ,NR2A和NR2BmRNA在海马各区呈现出一种相对一致的表达规律。在CA1区 ,NR2A和NR2BmRNA的表达分别在缺血再灌 6h和 12h降至低谷 ,然后回升 ,在缺血再灌 4 8h都升至高峰 ,之后表达再次下降 ,直至缺血后 7d ;在CA3区 ,该变化规律依然存在 ,不同的是表达变化的幅度明显减小 ;而在齿状回 ,缺血再灌 0 .5～ 72h ,二者的表达未见显著性变化 ;72h后 ,表达下降 ,直至缺血后 7d。②缺血后 2 4h ,凋亡细胞出现 ,主要位于海马CA1区 ,进行性增多 ,4 8h增加更为明显 ,缺血后 72h达高峰 ;然后凋亡细胞有所减少 ,但至缺血后 7d ,依然存在。 结论 短暂性前脑缺血后 ,大鼠海马各区NR2A和NR2BmRNA的表达变化及细胞凋亡均存在着显著性差异 ;这种差异提示 ,缺血后 ,NR2A和NR2BmRNA的表达变化与海马的选择性易损现象和缺血性细胞凋亡之间可能存在着某种密切的关系。
ObjectiveTo explore the alterations of NMDA receptor subunits NR2A and NR2B mRNA expression and their relationship to apoptosis in hippocampus of rat following transient forebrain ischemia. MethodsIschemia(15 min)-reperfusion (0.5 h-7 d) (IR) animal model was established by the four-artery occlusion (4AO). In situ hybridization (ISH) and TUNEL staining and image processing and analysis system were used. Results①The expression of NR2A mRNA and NR2B mRNA had relative concordance in hippocampus after IR. In the CA1, their expression dropped to the lowest at IR 6 h and 12 h. Then the expression started to recover and both rised to the highest at IR 48 h. Then the expression started to decrease again until the IR 7 d. In the CA3, the pattern of NR2A and NR2B mRNA expression was similar to that in the CA1, but the range of the changing reduced obviously. In the dentate gyrus, the expression of NR2A and NR2B mRNA had no significant change before IR 72 h and started to decrease until the IR 7 d. ②The TUNEL positive cells were observed mainly in the CA1 at IR 24 h. They increased obviously at IR 48 h and rised to the highest at 72 h, then started to reduce, but still existed at IR 7 d. ConclusionBoth the alterations of NR2A and NR2B mRNA expression and the apoptosis are different at different regions of hippocampus of rat after IR. It is indicated that the alterations of NR2A and NR2B mRNA expression may contribute to the selective vulnerable phenomenon and ischemic apoptosis of hippocampus after transient forebrain ischemia.
基金
江苏省自然科学基金资助项目 (BK99192 )
江苏省麻醉学重点实验室开放课题 (K990 3 7)
