丙戊酸钠慢性作用及停药后对C6神经胶质瘤细胞释放谷氨酸和谷氨酰胺的影响

Effects of chronic valproic acid sodium treatment and withdrawal on glutamate and glutamine release of C6 glioma cells

目的本实验通过研究丙戊酸钠(VPA)慢性作用及停药后对C6神经胶质瘤细胞释放谷氨酸(Glu)和谷氨酰胺(Gln)的影响,来探讨丙戊酸钠的抗癫痫机制以及停药反跳机制。方法用含50 mg/L VPA的DMEM培养基将C6细胞培养2周后制成VPA慢性作用模型,采用高效液相色谱技术测定VPA慢性作用及停药后C6神经胶质瘤细胞Glu和Gln的释放量。结果VPA的慢性作用可促进C6细胞Glu的释放, VPA停药后Glu的释放水平迅速下降到明显低于正常对照组水平,至停药48h又开始明显上升至接近对照组水平;VPA的慢性作用使C6细胞Gln释放减少,停药后Gln释放逐渐增加,逐步向对照组水平恢复。结论VPA慢性作用可促进C6细胞Glu的释放、抑制Gln的释放,停药后Glu释放呈反跳性变化,而停药后Gln释放的变化较平稳,可能与停药反跳没有直接关系。

Objective To determine the effects of chronic valproic acid sodium (VPA) treatment and subsequent withdrawal onthe release of glutamate (Glu) and glutamine (Gln) by C6 glioma cells, so as to understand the role of Glu and Gln released byastrocytes in the antiepileptic mechanism of VPA and the rebound mechanism of VPA withdrawal. Methods C6 glioma cellsweremaintainedfor 2weeksinDMEMmediumcontaining 50mg/LVPAtoestablishthecellmodelofchronicVPAtreatment. High-performance liquid chromatography (HPLC) was performed to detect the levels of Glu and Gln released by C6glioma cells after chronic VPA treatment and subsequent withdrawal. Results Chronic VPA treatment increased Glu release ofC6 glioma cells, and subsequent VPA withdrawal resulted in sustained decrease in the Glu level, reaching the lowest level 12h after VPA withdrawal, which was obviously lower than the control level. Gradual but significant increase of Glu level wasthen observed to approach the control level till 48 h after VPA withdrawal. For Gln release, chronic VPA treatment resulted inits decrease while after VPA withdrawal, gradual increase occurred to recover the control level. Conclusions Chronic VPAtreatment can increase Glu and decrease Gln release by C6 glioma cells. Glu level undergoes a rebound in response to VPAwithdrawal, while the relatively even changes of Gln level in the same setting may not involve VPA withdrawal rebound mechanism.