中文摘要：

目的探索不同剂量亚砷酸钠暴露不同时间对诱导人永生化角质形成（HacaT）细胞活性氧（ROS）产生的影响以及低剂量亚砷酸钠预处理HaCaT细胞对诱导ROS水平改变的时间效应。方法设未预处理组[分别加入终浓度为0（对照）、0．15、0．6、2．5、10μmol／L的亚砷酸钠染毒8、24、72h1和预处理8h组（加入0．15I．Lmol／L亚砷酸钠预处理8h后，加入10txmol／L亚砷酸钠染毒8h）及预处理24h组（加入0．15Ixmol／L亚砷酸钠预处理24h后，加入10μmol／L亚砷酸钠染毒8h）。利用2’，7’-二乙酰二氯荧光素（DCFH—DA）通过流式细胞仪检测细胞内ROS水平。结果与对照组比较，各浓度亚砷酸钠染毒8h和0．6、2．5、10μmol／L亚砷酸钠染毒24h及0．6、2．5μmol／L亚砷酸钠染毒72h后HacaT细胞内ROS水平均较高，而0．15、10μmol／L亚砷酸钠染毒72h后HacaT细胞内ROS水平均较低，差异有统计学意义（P〈0．05）。亚砷酸钠染毒8h时，HaCaT细胞内ROS水平达到峰值；之后，低剂量（O．15、0．6μmol/L）亚砷酸钠染毒组HaCaT细胞内ROS水平于24h下降，72h有所回升，而高剂量（≥2．5μmol/L）亚砷酸钠染毒组HaCaT细胞内ROS水平则呈持续下降。预处理8h组HacaT细胞内ROS水平高于预处理24h组，差异均有统计学意义（P〈0．05）；与10μmol／L亚砷酸钠染毒未预处理HaCaT细胞8h组比较，预处理8h组HaCaT细胞内ROS水平较高，预处理24h组HaCaT细胞内ROS水平较低，差异均有统计学意义（P〈0．05）。结论HaCaT细胞急性暴露于亚砷酸钠后能够引起HaCaT细胞内ROS产生增加，而不同剂量亚砷酸钠暴露诱导HacaT细胞ROS水平的改变与暴露时间密切相关，且低剂量亚砷酸钠暴露对HaCaT细胞产生的适应性反应可能取决于其作用时问。

英文摘要：

Objective To explore the dose-time effect of sodium arsenite on reactive oxygen species （ROS） in HaCaT ceils. Methods HaCaT keratinocytes were divided into non-pretreated group（exposure to a final concentration of 0（control）, 0.15,0.6,2.5 and 10 μmol/L sodium arsenite for 8,24,72 h）,8 h-pretreatment group （exposure to 10 μmol/L of sodium arsenite for 8 h after pretreatment by 0.15 μmol/L sodium arsenite for 8 h） ,and 24 h-pretreatment group（exposure to 10 μmol/L of sodium arsenite for 8 h after pretreatment by 0.15 μmol/L sodium arsenite for 24 h）. The ROS level induced by sodium arsenite in HaCaT cells was detected by FCM （flow cytometry） with DCFH-DA. Results Compared with control group,the intracellular ROS levels in HaCaT cells, treated with various concentrations of sodium arsenite for 8 h and 0.6,2.5,10 μmol/L sodium arsenite for 24 h and 0.6,2.5 μmol/L sodium arsenite for 72 h,were higher,while the ROS levels in HaCaT cells treated with 0.15,10 μmol/L sodium arsenite for 72 h were lower,the difference was statistically significant （P〈0.05）. With sodium arsenite exposure time prolonged,the intracellular ROS levels in HaCaT cells kept higher,reached peak at the 8th hour,then decreased. But after 24 h-treatment,the ROS level in HaCaT cells treated with 0.15 μmol/L and 0.6 μmol/L sodium arsenite increased again. In 8 h-pretreatment group,the ROS level in HaCaT cells were higher than that in non-pretreated group and 24 h-pretreatment group,whereas the ROS level in HaCaT cells in 24 h-pretreatment group were lower than that in non-pretreated group,the differences were statistically significant （P〈0.05）. Conclusion Acute sodium arsenite exposure may increase the level of ROS in HaCaT cells with dose-time dependent manner.