中文摘要：

目的探讨低剂量砷长期暴露对HaCat细胞凋亡及其调控蛋白Bcl～2和Bax表达的影响。方法HaCat细胞暴露于浓度为O（对照）、0．05、0．10μmol／L的亚砷酸钠（NaAsO2），在体外培养15周后收集细胞，用流式细胞仪测定10000个细胞的凋亡发生水平，用蛋白印迹法（Westernblot）检测细胞Bcl-2和Bax蛋白表达水平。结果细胞凋亡率组间比较差异有统计学意义（F=17．19，P〈0．05）；其中0．05、0．10μmol／L组细胞凋亡率分别为（1．23±0．08）％和（1．04±0．06）％，与对照组（1．42±0．13）％比较显著降低（P均〈0．05），且0．10μmol／L组细胞凋亡率显著低于0．05μmol／L组（P〈0．05）。细胞调控蛋白Bcl-2、Bax表达组间比较差异有统计学意义（F值分别为107．38、346．45，P均〈0．05）；其中0．05、0．10μmol／L组Bcl-2蛋白表达分别为（143．89±7．74）％和（199．96±12．18）％，与对照组（100．00±1．45）％比较显著增高（P均〈0．05），且0．10μmol／L组Bcl-2蛋白表达显著高于0．05μmol／L组（P〈0．05）；0．05、0．10μmol／L组Bax蛋白表达分别为（70.78±1．53）％和（54．80±1．34）％，与对照组（100．00±3．09）％比较显著降低（P均〈0．05），且0．10μmol／L组Bax蛋白表达显著低于0．05μmol／L组（P〈0．05）。结论长期低剂量砷暴露对细胞凋亡的诱导作用降低，可能与调控蛋白Bcl-2表达升高、Bax表达降低有关。

英文摘要：

Objective To investigate the influence of low-dose, long-term arsenite exposure on keratinocyte （HaCat） cell apoptosis and the expression of Bcl-2 and Bax proteins. Methods HaCat cells were exposed to different concentrations of NaAsO2[0（control group）, 0.05, 0.10 μmol/L] for 15 weeks. A total of 10 000 cells in each group were measured to detect the level of apoptosis by flow cytometry. The protein expressions of Bcl-2 and Bax were determined by Western blotting method. Results The cell apoptosis rate was significantly different between groups （F = 17.19,P 〈 0.05）. Compared with that of the control [ （ 1.42 ± 0.13 ） % ], the apoptosis rates of the 0.05 and 0. 10 μmol/L groups [ （ 1.23 ± 0.08 ） % and （ 1.04 ± 0.06 ） % ] decreased significantly （all P 〈 0.05 ） ; the 0.10 μmol/L group was significantly lower than that of the 0.05 μmol/L group（P 〈 0.05）. The protein expressions of Bcl-2 and Bax were significantly different between groups （F = 107.38,346.45, all P 〈 0.05）. The protein expression of Bcl-2 of the 0.05 and 0.10μmol/L groups were （143.89 ± 7.74）% and （199.96 ± 12.18）%, respectively, which were significantly higher than that of the control group [ （100.00 ± 1.45 ）%, all P 〈 0.05 ] ; the 0.10μmoL/L group was significantly higher than that of the 0.05μmol/L group （P 〈 0.05）. The protein expression of Bax of the 0.05 and 0.10 μmol/L groups were （70.78 ± 1.53）% and （54.80 ± 1.34）%, respectively, which were markedly lower than that of the control group [ （100.00 ± 3.09）%, all P 〈 0.05 ]; the 0.10 μmol/L group was significantly lower than that of the 0.05 μmol/L group（P 〈 0.05）. Conclusion Decreased level of apoptosis induced by low level and long-term arsenic exposure may be associated with increased expression of Bcl-2 protein and decreased expression of Bax protein.