COX-2在脑缺血再灌注后的表达

Expression of cyclooxygenase-2 after focal cerebral ischemic reperfusion in rats

目的确定COX-2免疫组化的空间分布特点,以及mRNA RT-PCR产物表达的时间分布特征并测序.方法采用石蜡包埋的免疫组化技术,脑组织中RNA提取、RT-PCR技术及测序分析.结果局灶性脑缺血再灌注后COX-2阳性神经元多位于梗死边缘区,另外血脑屏障也可见COX-2免疫反应阳性.COX-2 mRNA RT-PCR的PCR产物相对量,在脑缺血再灌注后15～24 h明显增高(P＜0.01).结论COX-2介导着脑缺血再灌注后半暗带和血脑屏障的存活和死亡,在恰当的时间窗内针对COX-2的治疗可能对脑保护是有效的.

Objective To study the spatial distribution of cyclooxygenase-2 (COX-2), the expression in various time courses and base sequences of mRNA (RT-PCR) after cerebral ischemic-reperfusion in rats. Methods The spatial and temporal features of COX-2 following ischemic reperfusion were studied by immunohistochemistry in paraffin embedded brain tissue; mRNA was extracted and detected with RT-PCR technique; base sequences of the DNA product were determinated. Results Immunohistochemistry was used to determine the spatial features in the ischemic brain. The expression of COX-2 positive cells was found not only at the border of the infarct that exhibited the morphological characteristics of ischemic neurons, but also in neurons that appeared structurally normal. Expression was also found in blood-brain-barrier (BBB), and in neutrophilic cells with multilobular nuclei around small vessels. mRNA RT-PCR and base sequence determination were used to study expression of COX-2 in different the time courses. The COX-2 mRNA was up-regulated peaking at 15~24 h in rats after focal ischemic reperfusion. Conclusion COX-2 plays a crucial role in protecting BBB and penumbra after focal cerebral ischemic reperfusion. The inhibition of COX-2 expression in an appropriate time course might be a potential protective treatment in rats.