短暂性前脑缺血后大鼠海马各区NMDA受体亚单位NR2A和NR2B mRNA的表达变化

应用原位杂交组织化学和图像处理与分析的方法 ,观察短暂性前脑缺血 (15 m in)再灌注 (0 .5 h～ 7d)大鼠海马各区NR2 A和 NR2 B m RNA的表达变化 ,探讨二者在缺血性脑损伤中的作用。结果发现 ,缺血后 ,NR2 A和 NR2 B m RNA在海马各区呈现出一种相对一致的表达。在海马 CA1 区 ,NR2 A和 NR2 B m RNA的表达分别在缺血再灌 6h和 12 h降至低谷 (P<0 .0 5 ) ,然后表达开始回升 ,在缺血再灌 48h都升至高峰 (P<0 .0 5 ) ,之后表达再次下降 ,直至缺血后 7d(P<0 .0 5 ) ;在海马 CA3区 ,二者的表达变化规律与 CA1 区相似 ,不同的是表达变化的幅度明显减小。在齿状回 ,缺血后 0 .5 h～ 72 h,NR2 A和 NR2 B m RNA的表达未见显著性变化 ,72 h后表达开始下降 ,直至缺血后 7d(P<0 .0 5 )。以上结果提示 ,短暂性前脑缺血后 ,NR2 A和 NR2 B m R-NA在大鼠海马各区表达变化的模式不同 ,这种不同可能与海马的选择性易损现象和迟发性细胞死亡有关

ALTERATIONS OF NMDA RECEPTOR SUBUNITS NR2A AND NR2B mRNA EXPRESSION IN HIPPOCAMPUS OF RAT FOLLOWING TRANSIENT FOREBRAIN ISCHEMIA

By in situ hybridization (ISH) and image processing and analysis system, we observed the alterations of NR2A and NR2B mRNA expression in hippocampus of rat following transient forebrain ischemia. The ischemia(15 min) reperfusion(0.5 h-7 d) (IR) animal model was created by the four artery occlusion (4AO). The results showed that the expression of NR2A and NR2B mRNA had relative concordance in regions of hippocampus after IR. In the CA 1, the expression of NR2A and NR2B mRNA dropped to the lowest at 6 h and 12 h of IR(P<0.05). Then the expression started to recover and both rised to the highest at 48 h of IR(P<0.05). And then the expression started to decrease again until the 7 d of IR(P<0.05). In the CA 3, the pattern of NR2A and NR2B mRNA expression was similar to that in the CA 1. The variousness was that the range of the expression change obviously decreased. And in the dentate gyrus, before 72 h of IR, the expression of NR2A and NR2B mRNA had no significant change and then the expression also started to decrease until the 7 d of IR(P<0.05). The results indicate that the alterations of NR2A and NR2B mRNA expression showed a different pattern in regions of rat hippocampus after IR. This difference hint that the alterations of NR2A and NR2B mRNA expression after IR may contribute to selective vulnerable phenomenon and delayed cell death of hippocampus.