大鼠脑缺血再灌注损伤后Cx43蛋白的表达模式

目的：建立大鼠大脑中动脉闭塞（MCAO）缺血再灌注模型,探索再灌注后Cx43蛋白的表达模式。方法75只大鼠随机分为MCAO组（60只）和假手术组（15只）。MCAO组均行MCAO手术,术后根据缺血再灌注时间分为0.5、4、12、24 h 4个亚组,每组15只；假手术组不插入线栓。各组进行改良神经损伤严重程度评分（mNSS）、脑组织TTC染色及神经元尼式染色,Western blot及免疫组织化学方法检测各组脑组织Cx43蛋白的表达并进行统计学分析。结果 MCAO组造模成功率75%。MCAO组大鼠mNSS评分明显高于假手术组（P＜0.05）,脑梗死面积增加,额顶叶皮质区神经元大量损伤。Western blot结果显示：假手术组及MCAO 0.5、4、12、24 h组Cx43表达量分别为0.23±0.12、0.58±0.18、0.78±0.07、0.61±0.05和0.27±0.07, MCAO 0.5、4、12 h组与假手术组差异均有统计学意义（P＜0.05）,而MCAO 24 h组与假手术组差异无统计学意义（P＞0.05）。免疫组化结果显示：MCAO组侧脑室下区Cx43的表达在0.5 h开始升高,4 h达高峰,12 h逐渐下降,直至24 h恢复基线水平；与Western blot结果一致。结论 Cx43蛋白在脑缺血性再灌注损伤发生、发展中起重要作用。

Expression patterns of connexin 43 protein after cerebral ischemia reperfusion injury in rats

Objective To establish the model of middle cerebral artery occlusion （MCAO） and ischemia reperfusion for exploring the expression patterns of connexin 43 （Cx43） protein after reperfusion. Methods Seventy-five rats were randomly divided into MCAO group （n=60） and sham operation group （n=15）. The rats in MCAO group underwent MCAO operation, and were divided into 0.5, 4, 12 and 24 h subgroups according to the ischemia reperfusion time after the operation, with 15 rats in every group, while those in the sham operation group were not inserted of the suture thread. All the groups were investigated by modified neurological severity score （mNSS）, TTC staining and neuron Nissl staining. The expression of Cx43 in the brain was detected by Western blot and immunohistochemistry, and statistical analysis was performed. Results The success rate of modeling was 75%in MCAO group. Compared with sham operation group, the mNSS scores increased significantly （P〈0.05）, cerebral infraction area increased and the neurons were damaged in frontal and parietal cortex area in MCAO group. The Cx43 expressions were respectively 0.23±0.12, 0.58±0.18, 0.78±0.07, 0.61±0.05 and 0.27±0.07 in MCAO 0.5, 4, 12 and 24 h groups and sham operation group by Western blot. Significant differences were found between MCAO 0.5, 4, 12 h groups and sham operation group （P〈0.05）, while no significant difference was found between MCAO 24 h group and sham operation group （P〉0.05）. The expression of Cx43 in subventricular zone started to increase at 0.5 h, reached the peak level at 4 h, decreased gradually at 12 h and returned to baseline level at 24 h by immunohistochemistry, which was similar to the results from Western blot. Conclusion Cx43 protein plays a pivotal role in the development and progression of cerebral ischemia reperfusion injury.