TNFα刺激的星形胶质细胞条件培养液对海马神经元的兴奋作用(英文)

THE EXCITATIVE EFFECT OF TNFα-ACTIVATED ASTROCYTIC CONDITIONED MEDIUM ON HIPPOCAMPAL NEURONS

为了探讨肿瘤坏死因子-α(tumor necrosis factor-α,TNFα)刺激的星形胶质细胞对神经元的作用,本研究将体外纯化培养的大鼠海马星形胶质细胞,用反相高效液相法测定TNFα刺激后细胞培养液内谷氨酸的含量;将TNFα刺激后的星形胶质细胞条件培养液(astrocytic conditioned medium,ACM)作用于培养的海马神经元,运用免疫细胞化学方法和图像分析技术研究神经元NF-κBp65和谷氨酸的表达。结果表明:(1)TNFα可明显促进星形胶质细胞释放谷氨酸,(2)ACM作用1 5 min即可诱导神经元NF-κBp65的核表达,30 min达高峰,180 min恢复至对照水平,(3)ACM作用60 min可使谷氨酸免疫反应阳性神经元平均光密度明显升高,持续至240 min。提示,TNFα刺激的星形胶质细胞可通过释放谷氨酸等可溶性物质使神经元快速激活、兴奋性升高。

To observe the effect of astrocytes activated by stimulation of tumor necrosis factor-α(FNFα) on neurons, the content of glutamate in the supernatant of purified cultured hippocampal astrocytes stimulated by TNFα(1 ng/ml) of rat were measured by high performance liquid chromatography (HPLC). The astrocytic conditioned medium (ACM) stimulated by TNFα was then collected and added to the supernatant of cultured hippocampal neurons. The expression of NF-κBp65 and glutamate was studied by immunocytochemical method. The results showed that (1) TNFα could promote the release of glutamate from astrocytes, (2) The expression of NF-κBp65 in the nucleus of neurons began to be induced at 15 min after ACM. The percentage and average optical density of the NF-κBp65- immunoreactivity(IR) positive nucleus reached the maximal level at 30 min and returned to the control level by 180 min, (3) The average optical density of Glu-IR positive neurons began to increase markedly 60 min after ACM and refuned to the normal at 240 min. The results indicate that neurons can be quickly activated and the excitability of neurons can also be elevated through the neuro-active substance such as glutamate released by astrocytes pretreated with TNFα.