无机砷对肝细胞转录因子Nrf2及其调控蛋白表达影响

Effects of sodium arsenite on expressions of nuclear transcription factor Nrf2 and Nrf2-regulated proteins

目的探讨不同时间和不同浓度亚砷酸钠(NaAsO2)暴露对Chang肝细胞株NF-E2相关因子2(Nrf2)、及其调控的下游抗氧化酶NAD(P)H:醌氧化还原酶1(NQO1)和血红素单加氧酶-1(HO-1)蛋白表达的影响。方法25μmol/L NaAsO2作用Chang肝细胞2、4、6、12和24 h;或不同浓度的NaAsO2(10、25和50μmol/L)作用Chang肝细胞6 h,免疫印迹法(western blot)检测细胞内Nrf2、NQO1和HO-1的蛋白表达情况。结果 25μmol/L的NaAsO2可以明显诱导Chang肝细胞Nrf2、NQO1和HO-1的蛋白表达(P<0.01);Nrf2蛋白2 h开始明显诱导,4 h表达水平最高,此后随暴露时间的延长虽然表达有所下降,但持续至24 h仍明显高于对照组;NQO1的蛋白表达水平也从4 h开始增加并持续至24 h;HO-1的蛋白表达则从6 h开始明显诱导,且随暴露时间的继续延长表达持续上升,具有明显的时间-效应关系;10、25和50μmol/L NaAsO2染毒6 h,Nrf2、NQO1和HO-1的蛋白表达均随染毒剂量的增加而大量诱导,具有明显的剂量-效应关系(P<0.01)。结论 NaAsO2暴露能够诱导Chang肝细胞Nrf2、NQO1和HO-1蛋白表达增强,且具有一定的剂量-效应关系。

Objective To explore the effects of sodium arsenite （ NaAsO2 ） on the protein expression of transcription factor nuclear factor erythroid 2-related factor 2 （Nrf2） and Nrf2-regulated downstream anti-oxidant enzymes in Chang liver cells. Methods Chang liver cells were treated with NaAsO2 （25 mol/L） for 2,4,6,12, and 24 hours or NaAsO2 at different doses of 10,25, and 50 mol/L for 6 hours. Western blot assay was used to detect the protein expression of Nrf2, NAD （P） H ： quinone oxidoreductase （ NQO1 ）, and heme oxygenase-1 （ HO-1 ）. Results NaAsO2 exposure of 25 p.mol/L could significantly induce Nrf2 ,NQO1, and HO-1 protein expressions in Chang liver cells. Nrf2 protein level was higher than control cells 2 hours after NaAsO2 exposure and approached the peak 4 hours after the exposure. NQOI protein level increased from 4 to 24 hours after the exposure. The protein expression of HO-1 was induced 6 hours after the exposure with a time-effect response. When the cells were treated with 10,25, and 50 μmol/L of NaAsO2 for 6 hours, dose-effect response was observed. Conclusion NaAsO2 could increase protein expression of Nrf2, NQO1, and HO-I in Chang liver cells with a dose-effect response.