星形胶质细胞对β-淀粉样蛋白诱导神经元凋亡的影响

Effects of astrocytes on the Aβ-induced neuronal apoptosis

目的:于大鼠海马原代培养的细胞模型中明确星形胶质细胞(Astrocytes,AS)在β-淀粉样蛋白(Am-yloid-β,Aβ)诱导的神经元凋亡中是否发挥作用,以及其发挥作用的主要方式。方法:建立4天龄Wistar大鼠海马原代混合培养体系(MIX-S)、纯化原代AS培养体系(AS-S)及纯化原代神经元培养体系(NE-S),用Aβ处理三种不同体系细胞,24 h后收集三种培养液(MNE-Aβ24 h、MAS-Aβ24 h、MMIX-Aβ24 h)及control组三种培养液(MNE-control、MAS-control、MMix-control)。在下一批NE-S和MIX-S培养细胞中,分别用不同培养液或Aβ处理24 h后应用TUNEL法检测细胞凋亡数量的变化。结果:Aβ处理后NE-S凋亡比例显著高于MIX-S,其中MIX-S凋亡与control组相近,MIX-S表现出较弱的Aβ毒性易感性。比较Aβ处理24 h后收集的培养液(MAβ24 h,Aβ前处理)与对照组培养液(Mcontrol)再加Aβ处理(Aβ后处理)培养细胞,发现Aβ前处理(MNE-Aβ24 h、MAS-Aβ24 h)比Aβ后处理(MNE-control、MAS-control再加Aβ)诱导NE-S凋亡的效果更加显著。而Aβ前、后处理对MIX-S组神经元诱导凋亡的效果类似,接近Control组凋亡比例。结论:AS参与保护Aβ诱导的海马神经元凋亡,其保护作用依赖于AS与神经元构建的MIX-S完整性而并不是由AS分泌入培养液的成分介导。单纯AS-S在Aβ刺激下不仅失去保护功能,且释放促凋亡物质。

Objective： The objection is to explore whether astrocytes play a role in Aft-induced neuronal apoptosis in primary cultured rat hippocampal cells, and the related mechanisms. Methods： First, we established the 4-day-old Wistar rat hippoeampal primary mixed culture system （MIX-S）, and the purified primary astrocytic culture system （AS-S）, as well as the purified primary neuronal culture system （NE-S）. Then all the culture systems were treated by A[3 and the different media were collected. The next NE-S and MIX-S were treated by different collected media or A[3 for 24 h. Subsequently the number of apoptotic cells was detected by TUNEL method. Results： Overall the apoptosis in NE-S treated by Aβ were significantly higher than that of MIX-S, whereas the apoptosis in MIX-S after A[3 treatment were similar to the control group, and MIX-S showed a lower susceptibility to toxicity. We found that, for NE-S, MNE.Aβ 24 h and MAS_Aβ 24 h significantly potentiated Aft-induced apoptosis compared to direct A[3 treatment groups. However, for MIX-S, there was no significant difference among the groups treated by different medium. Conclusion： Astrocytes play a protective role in Aβ-induced apoptosis in hippocampal cells. The protective role of AS does not depend on AS medium but the integrity ofthe MIX-S constructed by AS and neurons, and AS-S treated by Aβcould release proapoptotic substances.