大鼠缺血性脑损伤后室管膜下区miR-124的动态变化及意义

Dynamic change and significance of miR-124 expression in subependymal zone after ischemic brain injury in rats

目的观察脑缺血后室管膜下区(SEZ区)miR-124及Sox9 mRNA的表达变化,探讨miR-124对脑缺血后神经干细胞增殖分化的影响。方法 12只雄性SD大鼠随机分为实验组9只和对照组3只。实验组制作大脑中动脉缺血再灌注模型,分别于造模后第l、3、7天处死3只大鼠,取SEZ区用于实验;对照组仅暴露动脉。采用免疫荧光细胞染色法检测Nestin的表达,实时PCR检测miR-124及Sox9 mRNA的表达水平。结果实验组SEZ区Nestin阳性细胞数较对照组明显增加,且在造模后1、3、7 d呈递增趋势(P<0.05);实验组miR-124表达显著上调,造模后1、3、7 d分别为对照组的(1.63±0.13)、(3.67±0.28)、(2.08±0.11)倍(P<0.05);实验组Sox9 mRNA表达显著下调,造模后1、3、7 d分别为对照组的0.85±0.90、0.29±0.34、0.49±0.36(P<0.05)。结论脑缺血可促进SEZ区神经干细胞增殖,在神经细胞新生过程中miR-124表达上调,同时其靶基因Sox9 mRNA表达下调。

Objective To observe the changes ofmiR-124 and Sox9 mRNA expressions in subependymal zone （SEZ）, and explore the influence ofmiR-124 on neural stem cells （NSC） proliferation and differentiation after cerebral ischemia. Methods Twelve male SD rats were randomly divided into experimental group （n = 9） and control group （n = 3）. The middle cerebral artery occlusion and reperfusion model was established in the experimental group, and 3 rats were killed on 1, 3, 7 d after modeling respectively, then the SEZ in ischemic side was used in the experiment. The rats were only exposed of the middle cerebral artery in the control group. The level of Nestin expression was detected by immunofluorescence staining. The levels of miR-124 and Sox9 mRNA were detected by Real-time PCR. Results Compared with the control group, the positive Nestin cells in the SVZ increased obviously, and showed a increasing trend on 1, 3, 7 d after modeling in the experimental group （P 〈 0.05）. The miR-124 expression was obviously up-regulated in the experimental group, being 1.63 ± 0.13, 3.67± 0.28, 2.08 ± 0.11 times that in the control group respectively （P 〈 0.05）. The Sox9 expression was obviously down-regulated in the experimental group, being 0.85 ± 0.90, 0.29 ± 0.34, 0.49 ± 0.36 times that in control the group respectively （P 〈 0.05）. Conclusion Ischemic injury may promote the proliferation of endogenous neural stem cells in the SEZ. The miR-124 expression could be up-regulated and Sox9 down-regulated in the neurogenesis after ischemic injury.