局部脑缺血再灌注损伤小鼠脑组织TMEM166的表达及其与脑细胞凋亡的关系

目的:观察跨膜蛋白166(Transmembrane protein 166,TMEM166)基因在小鼠局部脑缺血再灌注损伤(MCAO)后的表达改变及其对脑细胞凋亡的影响。方法:C57/BL6J雄性小鼠50只,体重22-28 g,采用线栓法制作MCAO模型,缺血后动物随机分为再灌注6、12、24、48 h组。采用免疫组化染色的方法观察缺血侧大脑TMEM166、Caspase 3的阳性细胞数目,TUNEL标记法检测细胞凋亡情况,Western blot检测不同再灌注时间点TMEM166、Caspase 3蛋白水平的表达。结果:缺血侧TMEM166的表达随着再灌注时间的延长而增加,24 h达到高峰,48 h后逐渐下降;再灌注6 h后Caspase 3观察到有表达,同样随着再灌注时间而升高,24 h达到高峰。缺血侧细胞凋亡数量变化趋势与TMEM166基本一致,对侧大脑半球上述指标无明显变化。结论:小鼠局部脑缺血再灌注损伤时伴有TMEM166的表达升高,可能通过激活Caspase 3引起脑细胞凋亡。

Effect of TMEM166 on Neuron Apoptosis in Mice after Focal Brain Ischemia Reperfusion Injury

ABSTRACT Objective: To investigate the expression of TMEM166(Transmembrane protein 166) and its effect on neuron apoptosis in mice after middle cerebral artery occlusion (MCAO). Methods: Fifty C57/BL6J male mice weighing 22-28 g were randomly divided into five groups according to different reperfusion time points at 6, 12, 24 and 48 h, respectively. TMEM166 and Caspase 3 were measured by immunochemistry staining. TUNEL staining was conducted to observe the neuron apoptosis. Protein levels of TMEM166 and Caspase 3 were detected by Western blot. Results: TMEM166 was induced in mice after cerebral ischemia reperfusion injury, and it has peaked at 24 h after injury in the ischemia hemisphere. Cleaved Caspase 3 began to increase at 6 h following MCAO, which then kept going up over time and also reached the highest level at 24 h after ischemia insult. Changing pattern of TMEM166 level in this process was consis- tent with the changes of TUNEL positive cell numbers. No changes of TMEM166 was found in the contralateral hemisphere. Conclusion: TMEM166 was induced after MCAO, and it could lead to cell apoptosis by activating Caspase 3.