AKT/mTOR信号分子在小鼠海马发育中的表达

Expression of AKT/mTOR in the development of mice hippocampus

目的:观察蛋白激酶B(AKT)/哺乳动物雷帕霉素靶蛋白(mTOR)信号分子在小鼠胚胎发育晚期和生后早期海马中的表达变化。方法:在E18、P1、P7、P14、P21和P28时间点取昆明小鼠海马组织,利用4′,6-二脒基-2-苯基吲哚(DAPI)染色观察海马细胞数量;利用免疫组织化学和Western Blot检测各时间点海马中AKT和mTOR蛋白的表达变化。结果:DAPI染色显示,E18~P21,海马齿状回(DG)颗粒细胞层和阿蒙角(CA)锥体细胞层细胞先逐渐增多,P7最多,之后逐渐减少(P<0.01);P28与P21相比,细胞数量无显著性差异(P>0.05)。免疫组织化学技术显示,E18~P7,海马DG和CA的AKT和mTOR阳性细胞逐渐密集,光密度逐渐增大;P7阳性细胞最密集,光密度最大;P14~P21,阳性细胞逐渐稀疏,光密度减小(P<0.05)。P28与P21相比,DG的AKT阳性细胞更稀疏,光密度减小(P<0.05),CA的AKT阳性细胞、DG和CA的mTOR阳性细胞的密集程度无明显改变,光密度无显著性差异(P>0.05)。Western Blot结果显示:E18~P21,AKT和mTOR的表达均表现为先逐渐增高,P7达高峰,之后逐渐降低(P<0.01);P28与P21相比,AKT表达无显著性差异(P>0.05),mTOR表达减少(P<0.01)。结论:AKT和mTOR蛋白在小鼠胚胎发育晚期和生后早期的海马中呈高表达。AKT/mTOR信号通路可能与海马发育密切相关。

Objective:To study the expression of protein kinase B(AKT)and mammalian target of rapamycin(mTOR)in the mice hippocampus in the later stage of embryonic development and early stage of postnatal development.Methods:Hippocampus of Kunming mice on embryonic(E)18,postnatal(P)1,P7,P14,P21 and P28 were studied.4′,6-diamidino-2-phenylindole(DAPI)staining was used to check the number of cells in hippocampus.Immunohistochemistry and Western Blot were used to observe the expression of AKT and mTOR proteins in hippocampus at various points in time.Results:DAPI staining revealed that,from E18 to P21,the number of cells in hippocampal dentate gyrus(DG)stratum granulosum and Ammon’s horn(CA)pyramidal layers increased gradually firstly,peaked on P7,then decreased gradually(P<0.01).There was no significant difference in the number of cells,compared P28 with P21(P>0.05).Immunohistochemistry showed that,from E18 to P7,AKT and mTOR positive cells were increasingly denser and the optical density increased gradually in DG and CA of hippocampus.Then the peak appeared on P7 with the densest positive cells and the highest optical density.From P14 to P21,the positive cells were gradually sparse and the optical density decreased gradually(P<0.05).On P28,the AKT positive cells in DG were more sparse and the optical density was lower than those on P21(P<0.05).There was no significant difference in the density of AKT positive cells in CA,mTOR positive cells in DG and CA and their optical density,compared P21 with P28(P>0.05).Western Blot showed that the expression of AKT and mTOR increased firstly,peaked on P7 and then decreased gradually(P<0.01).There was no significant difference in the expression of AKT,compared P21 with P28(P>0.05).But the expression of mTOR decreased on P28(P<0.01).Conclusion:AKT and mTOR are highly expressed in the hippocampus in the later stage of embryonic development and early stage of postnatal development.AKT/mTOR signal pathway may be closely related to mice hippocampus development.