β淀粉样肽31-35介导的神经细胞线粒体损伤及机制研究

Study on Damage and Mechanism of Mitochondria of Neurons Induced by Aβ 31-35

目的研究Aβ31-35介导的神经细胞线粒体毒性作用,并探讨其可能的作用机制。方法24h龄Wistar大鼠大脑皮质神经细胞原代培养,培养48h后在培养基中分别加入Aβ31-35和Aβ25-35建立大脑神经细胞线粒体损伤模型。24h后,流式细胞术检测神经细胞线粒体通透性转变孔道(PTP)开放;酶法检测神经细胞线粒体氧化还原平衡体系GSH/GSSG比率的改变;激光共聚焦显微术检测神经细胞活性氧(ROS)水平。结果与对照组相比,Aβ31-35和Aβ25-35处理组神经细胞线粒体膜电位显著降低(P<0.05),反映线粒体颗粒大小的前向光散射(FSC)和反映线粒体颗粒性状的侧向光散射(SSC)分布峰由低道数向高道数移动,表明线粒体肿胀、颗粒性状发生改变;Aβ31-35和Aβ25-35处理组神经细胞线粒体GSH/GSSG比率显著降低,与对照组相比差异有统计学意义(P<0.01);Aβ31-35和Aβ25-35处理可以使神经细胞ROS水平显著增高,且与对照组相比差异有统计学意义(P<0.01)。结论Aβ31-35同Aβ25-35一样可引起神经细胞线粒体毒性作用,其作用机制与Aβ介导的神经细胞线粒体氧化损伤有关。

Objective To study the damage of mitochondria of neurons induced by Aβ31-35 and explore its possible mechanism. Method Cerebral cortexes of newborn 24 h Wistar rats were dissected to get neurons for primary culture.The neurons were planied into 2 ml culture plate at a density of 2×10s cells/ml to grow for 48 h.Then, Aβ31-35 and Aβ25-35 were respectively added into the medium to establish mitochondria damaged model of neurons. After treating neurons with Aβ31-35 or Aβ25-35 for 24 h, the mitochondrial permeability transition pore （PTP） of neurons was investigated by flow cytometry. The relative value of GSH/GSSG in mitochondria of neurons was measured by assay kit; Confocal microscopy was used to detect the level of reactive oxygen species （ROS）.Each experiment was repeated 3 times. Results Comparing with control group, Aβ31- 35 and Aβ25-35 treatment group caused significant decrease of the mitochondfial membrane potential （ P〈0.05） and the relative value of GSH/GSSG （P 〈 0.01 ）. The distribution of peaks of forward scatter （FSC） and side scatter （SSC） shifted from low channel to high channel. It was indicated that mitochondria swelled and characters of particle changed. Aβ31-35 and Aβ25-35 increased the level of ROS in neurons and there was statistic significance when they were compared with the control group （P〈0.01 ）. Conclusion Both Aβ31-35 and Aβ25-35 could induce the toxicity of mitochondria of neurons, and its mechanism might be related to oxidative damage of mitochondria of neurons induced by Aβ.