砷对星形胶质细胞分泌D-丝氨酸影响

目的通过观察砷对星形胶质细胞(AST)分泌D-丝氨酸的影响,探讨砷的智力损伤作用机制。方法以原代培养脑AST为试验对象,在含砷浓度分别为0、2.5、5、10 μmol/L的培养液中培养24 h,采用高效液相色谱法检测D-丝氨酸水平,Western blot法检测丝氨酸消旋酶(SR)蛋白表达水平,荧光双波长分光光度计法检测细胞内游离钙离子([Ca²⁺]_i)浓度。结果与对照组比较,2.5、5、10 μmol/L砷暴露后,AST分泌D-丝氨酸的水平[分别为(21.580±1.313)、(21.936±1.539)、(23.401±1.648) μmol/L]和SR蛋白表达水平[分别为(1.327±0.122)、(1.397±0.105)、(1.403±0.104)]均明显升高,10 μmol/L砷暴露组AST内[Ca²⁺]_i含量明显升高。结论砷暴露可引起AST分泌D-丝氨酸水平增加,该过程可能与砷暴露引起AST内SR的表达水平增强以及[Ca²⁺]_i升高有关。

Effects of arsenite on D-serine released from astrocytes and its related mechanism

Objective To investigate the intellectual impairment induced by arsenite through studying the effects of arsenite on D-serine released from astrocytes and its related mechanism.Methods The primary cultured astrocytes were divided into four groups randomly,in which astrocytes were exposed to 0,2.5,5 or 10 μmol/L arsenite for 24 hours.The level of D-serine was measured with high performance liquid chromatography(HPLC);the protein expression of serine racemase(SR)was measured with western blot;the intracellular free Ca²⁺ concentration([Ca²⁺]_i)in astrocytes was measured with fluorescence dual wavelength spectrophotometer.Results Compared with those in control group,the levels of D-serine released from astrocytes(21.580±1.313,21.936±1.539 and 23.401±1.648 μmol/L)and the protein expression of SR(1.327±0.122,1.397±0.105,and 1.403±0.104)increased significantly in groups treated with arsenite;and [Ca²⁺]_i(0.26±0.01 μmol/L)in the group treated with 10 μmol/L arsenite increased significantly.Conclusion Arsenite could increase the level of D-serine released from astrocytes and its mechanism could be related with the increasing protein expression of SR and the elevated [Ca²⁺]_i in astroytes induced by arsenite.