高浓度谷氨酸诱导胶质瘤细胞凋亡及其机制

Apoptosis of glioma cells induced by high concentration glutamate and its mechanism

目的研究高浓度谷氨酸对原代培养人脑胶质瘤细胞的凋亡诱导作用,进一步探讨其凋亡的可能机制。方法对新鲜的人脑胶质瘤进行体外原代培养,不同浓度的谷氨酸作用不同时间,形态学观察;四甲基偶氮唑盐(MTT)法检测肿瘤细胞生长抑制率;流式细胞术检测肿瘤细胞凋亡率;激光共聚焦显微镜检测细胞膜内游离钙离子的浓度变化。结果原代培养胶质瘤细胞的生长抑制率随谷氨酸浓度的增加呈递增趋势。25、50和100mmol/L谷氨酸作用胶质瘤细胞48h的凋亡率分别为9.65%、31.13%和20.35%。脑胶质瘤原代培养细胞内钙离子浓度在谷氨酸作用后明显升高,与对照组相比有显著性差异(P<0.01);但不同浓度组、24h和48h组之间钙离子的浓度无显著性差异(P>0.05)。结论高浓度的谷氨酸可诱导原代培养人脑胶质瘤细胞凋亡,凋亡率在一定范围内呈明显的剂量依赖性。钙离子在谷氨酸诱导的细胞凋亡中起重要作用。

Objective To study the apoptosis of primary cultured human glioma ceils induced by high concentration glutamate and to explain the mechanism of apoptesis. Methods Primary human glioma cells were cultured in vitro. Morphological changes were investigated by using microscope after the treatment with different concentrations of glutamate. 4, 5-dimethyl thiazole （MTT） was applied to assay the growth inhibitory rate of various concentrations of glutamate. Cells were analyzed by flow cytometry （FCM） to determine the apoptesis rates after the treatment of different concentrations of glutamate. The concentrations of Ca^2＋ in glioma cells were detected by confocal laser scanning microscopy. Results The gowth inhibition rate of glioma cells increased with increasing concentrations of glutamate. When the concentrations were 25, 50 and 100 mmol/L, the apoptotic rates were 9.65%, 31.13%and 20.35%respectively. The concentrations of calcium in glioma cells were significantly higher after the treatment of glutamate （ P 〈 0. 01 ）. There was no significant difference between different concentrations of glutamate, and it was the same case between 24 h and 48 h （P 〉 0. 05）. Conclusion High concentration of glutamate can induce apoptosis of primary cultured human glioma cells and the apoptosis rate increases with the concentration. Ca^2＋ is supposed to play a main role of the pro-apoptotic effect.