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目的检测急性亚砷酸钠作用小鼠胰岛β细胞的Nrf2及其调控的II相解毒酶的表达情况。方法4μmol/L亚砷酸钠(NaAsO2)作用于MIN6细胞2、6、12、18、24h;利用Western blotting检测亚砷酸钠暴露不同时间点细胞核、细胞质和细胞总的Nrf2蛋白表达;应用Real-time PCR检测不同时间点Nrf2及其调控的II相解毒酶NAD(P)H:醌氧化还原酶1(Nqo1)和血红素氧化酶1(Hmox-1)mRNA表达。结果亚砷酸钠暴露2h,Nrf2蛋白表达增多并达到高峰,之后随时间的延长Nrf2蛋白表达逐渐降低。Nrf2核蛋白表达的时间效应性与细胞总的Nrf2表达完全一致。但不同时间点的亚砷酸钠暴露对Nrf2的mRNA表达未出现显著影响。Nqo1和Hmox-1表达亦存在时间效应性,即亚砷酸钠暴露后2h,Nqo1和Hmox-1 mRNA表达开始增高,6h达到高峰,随后逐渐下降。结论急性亚砷酸钠暴露后,能够诱导小鼠胰岛β细胞内Nrf2的蛋白表达,并促进其转位进入细胞核,调节其下游II相解毒酶Nqo1和Hmox-1的转录活性。
Objective To detect the expression of Nrf2 and its regulatory phase II detoxification enzyme in mouse pancreatic β-cells induced by acute sodium arsenite. METHODS: The cells were treated with 4μmol / L sodium arsenite (NaAsO2) for 2, 6, 12, 18 and 24 hours. The expression of Nrf2 in nuclei, cytoplasm and cells at different time points of arsenite exposure was detected by Western blotting. The expression of Nrf2 and its regulated phase II detoxification enzyme NAD (P) H: quinoloxidase 1 (Nqo1) and hemeoxygenase-1 (Hmox-1) mRNA were detected by time PCR. Results After exposure to sodium arsenite for 2h, the expression of Nrf2 increased and reached a peak, then the expression of Nrf2 decreased gradually with the prolongation of time. The time-effect of Nrf2 nuclear protein expression is consistent with the total Nrf2 expression in cells. However, sodium arsenite exposure at different time points had no significant effect on the mRNA expression of Nrf2. The expression of Nqo1 and Hmox-1 was also time-dependent. After 2h exposure to sodium arsenite, Nqo1 and Hmox-1 mRNA expression began to increase and peaked at 6h, then decreased gradually. CONCLUSION: Acute sodium arsenite exposure can induce Nrf2 protein expression in pancreatic islet β cells and promote the translocation into the nucleus and regulate the transcriptional activity of the downstream phase II detoxifying enzymes Nqo1 and Hmox-1.