摘要目的:探讨亚砷酸钠（NaAsO 2）通过活性氧（ROS）蓄积及线粒体损伤诱导人肝细胞L-02凋亡的作用，为砷中毒的作用机制研究提供实验依据。 方法:体外培养L-02细胞，分为对照组、NaAsO 2组（10 μmol/L NaAsO 2）、N-乙酰半胱氨酸（NAC）组（5 mmol/L NAC）、NaAsO 2 + NAC组（10 μmol/L NaAsO 2、5 mmol/L NAC），培养24 h。分别用二氯二氢荧光素-乙酰乙酸酯（DCFH-DA）荧光探针法、JC-1染色法、硫氰酸荧光素/碘化丙啶（Annexin V-FITC/PI）双染法检测细胞内ROS水平、线粒体膜电位去极化比例和细胞凋亡率；用实时荧光定量PCR（qRT-PCR）和蛋白免疫印迹法（Western blot）检测半胱氨酸天冬氨酸蛋白酶3（Caspase3）、细胞色素C蛋白（Cyt-C）、线粒体DNA编码的细胞色素C氧化酶Ⅳ（COXⅣ）mRNA、蛋白表达水平。 结果:各组间细胞内ROS水平（3 857 392.33 ± 44 928.39、4 515 288.00 ± 32 660.64、3 670 150.67 ± 101 987.69、4 035 235.67 ± 99 995.30），线粒体膜电位去极化比例（2.16 ± 0.54、7.95 ± 0.52、2.70 ± 0.29、1.01 ± 0.23），细胞总凋亡率（1.45 ± 0.03、4.27 ± 0.17、1.87 ± 0.12、2.52 ± 0.35）比较差异有统计学意义（ F = 62.62、159.81、112.70， P均< 0.05）；各组间Caspase3、Cyt-C、COXⅣ mRNA表达水平比较差异有统计学意义（ F = 9.20、7.33、14.87， P均< 0.05）；各组间活化Caspase3（cleaved-Caspase3）、Cyt-C、COXⅣ蛋白表达水平比较差异有统计学意义（ F = 31.42、8.01、83.30， P均< 0.05）。与对照组比较，NaAsO 2组L-02细胞内ROS水平、线粒体膜电位去极化比例、细胞总凋亡率明显增高（ P均< 0.05）；Caspase3、Cyt-C mRNA和cleaved-Caspase3、Cyt-C蛋白表达水平明显增高（ P均< 0.05），COXⅣ mRNA和蛋白表达水平则显著降低（ P均< 0.05）。与NaAsO 2组比较，NaAsO 2 + NAC组细胞内ROS水平、线粒体膜电位去极化比例、细胞总凋亡率明显下降（ P均< 0.05）；Caspase3 mRNA和cleaved-Caspase3蛋白表达水平明显降低（ P均< 0.05），Cyt-C mRNA和蛋白表达水平明显降低（ P均< 0.05），COXⅣ mRNA和蛋白表达水平明显增高（ P均< 0.05）。 结论:NaAsO 2可刺激L-02细胞产生大量ROS，诱发线粒体去极化，引发线粒体损伤，使Cyt-C向线粒体外释放增加，激活线粒体凋亡途径Caspase3蛋白酶而引起L-02细胞发生凋亡，这有可能是砷致肝损伤的主要作用机制之一。

abstractsObjective:To explore the mechanism of apoptosis induced by sodium arsenite (NaAsO 2) in human hepatic cells (L-02) through reactive oxygen species (ROS) accumulation and mitochondrial dysfunction, and provide experimental evidence for the mechanism of arsenic poisoning. Methods:L-02 cells were divided into control group, NaAsO 2 group (10 μmol/L NaAsO 2), N-acetylcysteine (NAC) group (5 mmol/L NAC), and NaAsO 2 + NAC group (10 μmol/L NaAsO 2, 5 mmol/L NAC), and were cultured in vitro for 24 h. The intracellular ROS level, mitochondrial membrane potential depolarization ratio and cell apoptosis rate were measured by dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence probe, JC-1 staining and Annexin V-FITC/PI double staining, respectively; the mRNA and the protein of Caspase 3, cytochrome C (Cyt-C) and cytochrome C oxidaseⅣ (COXⅣ) were detected by real time fluorescence quantitative PCR (qRT-PCR) and Western blotting, respectively. Results:There were statistically significant differences in intracellular ROS levels (3 857 392.33 ± 44 928.39, 4 515 288.00 ± 32 660.64, 3 670 150.67 ± 101 987.69, 4 035 235.67 ± 99 995.30), mitochondrial membrane potential depolarization ratios (2.16 ± 0.54, 7.95 ± 0.52, 2.70 ± 0.29, 1.01 ± 0.23) and total apoptosis rates (1.45 ± 0.03, 4.27 ± 0.17, 1.87 ± 0.12, 2.52 ± 0.35) between groups ( F = 62.62, 159.81, 112.70, P < 0.05). There were statistically significant differences in Caspase 3, Cyt-C, COXⅣ mRNA expression levels ( F = 9.20, 7.33, 14.87, P < 0.05) and in cleaved-Caspase 3, Cyt-C, COXⅣ protein expression levels( F = 31.42, 8.01, 83.30, P < 0.05) between groups. Compared with the control group, the intracellular ROS level, mitochondrial membrane potential depolarization ratio and total apoptosis rate were significantly increased ( P < 0.05); Caspase3, Cyt-C mRNA and protein expression levels were significantly increased ( P < 0.05), and COXⅣ mRNA and cleaved-Caspase 3, Cyt-C protein expression levels were significantly decreased ( P < 0.05) in NaAsO 2 group. Compared with the NaAsO 2 group, the intracellular ROS level, mitochondrial membrane potential depolarization ratio and total apoptosis rate of NaAsO 2 + NAC group were significantly decreased ( P < 0.05); the Caspase3, Cyt-C mRNA and cleaved-Caspase 3, Cyt-C protein expression levels were significantly decreased ( P < 0.05), the COX Ⅳ mRNA and protein expression levels were significantly increased ( P < 0.05). Conclusions:NaAsO 2 stimulates L-02 cells to produce excessive ROS, which induces mitochondrial depolarization and further triggers mitochondrial damage, resulting in increased release of Cyt-C and activation of the mitochondrial apoptosis pathway that Caspase 3 protein induces apoptosis in L-02 cells, which may be one of the main mechanisms of arsenic-induced liver injury.