GHS-R 1a敲除对小鼠下丘脑小胶质细胞表达的影响

Effect of growth hormone secretagogue receptor 1a knockout on the expression of microglial cells in the hypothalamus of mice

目的探讨生长激素促分泌受体1a(GHS-R 1a)敲除对小鼠下丘脑小胶质细胞表达的影响。方法选取12只6月龄GHS-R 1a^(-/-)雄性小鼠设为GHS-R1a^(-/-)组,12只同月龄野生型(WT)雄性小鼠设为WT组。采用高架十字迷宫(EPM)实验测试两组小鼠的焦虑水平,采用组织免疫荧光技术检测两组小鼠下丘脑小胶质细胞数量,采用实时荧光定量PCR(qRT-PCR)技术检测两组小鼠下丘脑离子钙结合接头分子1(Iba 1)、小胶质细胞活化蛋白CD 68和髓系细胞触发受体2(Trem 2)基因的表达水平。结果两组小鼠EPM实验结果无显著差异(P>0.05);组织免疫荧光技术检测结果显示,GHS-R1a^(-/-)组小鼠下丘脑中小胶质细胞数量显著多于WT组小鼠(t=4.61,P<0.05);qRT-PCR检测结果显示,GHS-R1a^(-/-)组小鼠下丘脑Iba 1和Trem 2 mRNA表达水平显著高于WT组小鼠(t=3.63、3.01,P<0.05),CD68 mRNA水平表达显著低于WT组小鼠(t=3.79,P<0.05)。结论GHS-R 1a基因敲除不影响小鼠的焦虑水平,但会导致小鼠下丘脑中小胶质细胞数量增加;GHS-R 1a可能在抑制小胶质细胞增殖及吞噬功能、促进小胶质细胞活化的过程中发挥调节作用。

Objective To investigate the effect of growth hormone secretagogue receptor 1a(GHS-R 1a)knockout on the expression of microglial cells in the hypothalamus of mice.Methods A total of 12 male GHS-R 1a^(-/-)mice,aged 6 months,were selected as GHS-R1a^(-/-)group,and 12 wild-type(WT)male mice of the same age were selected as WT group.The elevated plus maze(EPM)experiment was used to measure the level of anxiety in the two groups of mice,immunofluorescence assay was used to measure the number of microglial cells in the hypothalamus of the mice in the two groups,qRT-PCR was used to measure the gene expression levels of ionized calcium binding adaptor molecule 1(Iba 1),microglial activation protein CD 68,and myeloid cell trigger receptor 2(Trem 2)in the hypothalamus of the mice in both groups.Results There was no significant difference in the results of the EPM test between the two groups(P>0.05).Immunofluorescence assay showed that compared with the WT group,the GHS-R1a^(-/-)group had a significantly higher number of microglial cells in the hypothalamus(t=4.61,P<0.05).The results of qRT-PCR showed that compared with the WT group,the GHS-R1a^(-/-)group had significantly higher mRNA expression levels of Iba 1 and Trem 2(t=3.63,3.01,P<0.05)and a significantly lower mRNA expression level of CD 68 in the hypothalamus(t=3.79,P<0.05).Conclusion GHS-R 1a knockout does not affect the level of anxiety in mice,but it can increase the number of microglial cells in the hypothalamus of mice.GHS-R 1a may play a regulatory role in inhibiting the proliferation and phagocytosis of microglial cells and promoting the activation of microglial cells.