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目的探讨胰岛素样生长因子结合蛋白-3(IGFBP-3)、视网膜X受体α(RXRα)及信号转导子和转录激动子(STAT-1)在β-淀粉样肽1～42(Aβ1～42)诱导大鼠海马神经元凋亡中的可能作用。方法以原代培养的大鼠海马神经元为模型,分为对照组和Aβ1～42组,加入不同浓度的凝聚态Aβ1～42,原位缺口末端标记法(TUNEL)观察凋亡细胞的形态;免疫细胞荧光方法检测凋亡细胞及IGFBP3、RXRα阳性细胞;免疫印迹法检测RXRα蛋白和STAT-1蛋白的表达水平。结果20μmol/LAβ1～42作用大鼠海马神经元24h能明显诱导神经元凋亡,表现为TUNEL/DAPI染色出现阳性细胞;20μmol/LAβ1～42作用大鼠海马神经元3～6h后IGFBP3阳性细胞、RXRα阳性细胞、RXRα蛋白的表达水平均较对照组有明显增高(P<0.01),在较高水平保持一段时间后逐渐下降;而STAT-1蛋白的表达水平则显著降低(P<0.01)。结论IGFBP3/RXRα或STAT-1信号转导通路可能在Aβ1～42诱导大鼠海马神经元凋亡中起一定作用。
Objective To investigate the effect of insulin-like growth factor binding protein-3 (IGFBP-3), retinal X receptor alpha (RXRα), signal transducer and activator of transcription (STAT- 42) induces apoptosis in rat hippocampal neurons. Methods Primary cultured rat hippocampal neurons were divided into control group and Aβ1 ~ 42 groups. The morphological changes of apoptotic cells were observed by adding different concentrations of condensed Aβ1 ~ 42 and TUNEL. Immunofluorescent staining was used to detect apoptotic cells and IGFBP3, RXRα positive cells. Western blotting was used to detect the expression of RXRα protein and STAT-1 protein. Results The apoptotic neurons were induced by 20 μmol / LAβ1 ~ 42 for 24 h in hippocampal neurons, showing positive cells by TUNEL / DAPI staining. IGFBP3 positive cells were detected at 3-6 h in 20 μmol / The expression of RXRα protein and RXRα protein were significantly higher than those in the control group (P <0.01), and gradually decreased after a certain period of time while the expression of STAT-1 protein was significantly decreased (P <0.01). Conclusion IGFBP3 / RXRα or STAT-1 signal transduction pathway may play a role in the apoptosis of hippocampal neurons induced by Aβ1-42.