N-myc下游调节基因2在小鼠创伤性脑损伤模型中的时空表达

Spatial-temporal expression of N-myc downstream-regulated gene 2 in mouse brain after traumatic brain injury

目的探讨N-myc下游调节基因2(NDRG2)在小鼠创伤性脑损伤(TBI)后的时空表达.方法将雄性小鼠随机分为7组:sham、TBI 6 h、TBI 12 h、TBI 24 h、TBI 48 h、TBI 72 h、TBI 7 d.采用重物自由落体法制备小鼠脑损伤模型.采用免疫蛋白印迹法检测小鼠伤灶附近脑组织中NDRG2蛋白水平.采用免疫荧光法分析小鼠伤后NDRG2的细胞和亚细胞定位.采用Student-t检验依次分析TBI组与sham组NDRG2蛋白水平的差异.结果免疫蛋白印迹结果显示NDRG2蛋白在TBI后12 h开始显著升高至1.52倍(t=3.181,P<0.05),24h达到峰值1.92倍(t=5.032,P<0.01).免疫荧光结果显示NDRG2蛋白信号特异性位于星形胶质细胞.TBI后,NDRG2蛋白出现核转移现象和与原位末端标记法(TUNEL)信号共定位现象.结论NDRG2蛋白在TBI后表达升高,并伴有核转移及与TUNEL信号共定位,提示NDRG2参与TBI后细胞凋亡的发生发展.

Objective To explore the spatial-temporal expression of N-myc downstream-regulated gene 2(NDRG2)in mouse brain after traumatic brain injury(TBI).Methods Male mice were randomly divided into the following groups:sham,TBI 6 h,TBI 12 h,TBI 24 h,TBI 48 h,TBI 72 h,TBI 7 d.A modified weight-drop method was utilized to induce mice TBI model.Western blot was used to detect the NDRG2 protein levels.Immunofluorescence was used to explore the cellular and subcellular locations of NDRG2.Student t test was used for difference comparison of NDRG2 protein levels between TBI and sham mice.Results The results of western blot showed that theNDRG2 protein levels increased significantly from 12 hours after TBI(1.52 fold,t=3.181,P<0.05),peaked at 24 hours(1.92 fold,t=5.032,P<0.01).The results of immunofluorescence showed that NDRG2 signals were specifically located in astrocytes.Besides,we observed NDRG2 nuclear translocation and co-localization with terminal deoxynucleotidyl transferase dUTPnick end labeling(TUNEL)signal safter TBI.Conclusion NDRG2 protein levels significantly increased after TBI.Besides,the increased proteins were partly translocated into nucleus and were co-localized with TUNEL signals,indicating that NDRG2 was involved with apoptosis after TBI.