探讨两种硒化物对人结肠腺癌Caco-2细胞的毒性作用。将Caco-2细胞暴露在不同浓度的亚硒酸钠（SeIV）和硒代蛋氨酸（SeMet）中培养24 h，用Annexin V-FITC/PI双染色法检测在同样浓度的SeIV和SeMet培养下细胞的凋亡率,并设置不做硒处理的空白对照。用MTT法检测细胞存活率；检测细胞培养液中乳酸脱氢酶（LDH）释放率、细胞内的超氧化物歧化酶SOD活力和谷胱甘肽GSH的含量。相同浓度时（0.8 μg Se/mL），与对照相比，SeIV诱导细胞凋亡显著率上升（p<0.05），SeMet变化不显著。一定浓度的SeIV（≥0.4 μg Se/mL）和SeMet（≥40 μg Se/mL）与对照组相比均显著降低细胞的存活率（p<0.05）；随着Se含量的升高细胞的存活率呈下降趋势，SeIV、SeMet的IC50分别为2.56、215.55 μg Se/mL。当SeIV浓度为≥0.8 μg Se/mL，SeMet浓度为≥40 μg Se/mL时，细胞的LDH释放率均显著高于对照组（14.80%）（p<0.05）。当SeIV浓度≥4 μg Se/mL，SeMet≥4 μg Se/mL时，细胞的SOD活性均显著低于对照组（56.76 U/mg prot）（p<0.05）。当SeIV浓度≥4 μg Se/mL，SeMet浓度为160 μg Se/mL时，细胞的GSH含量均显著低于对照组（61.67 μg/mg prot）（p<0.05）。一定浓度的SeIV和SeMet会使Caco-2细胞产生氧化应激而导致细胞毒性，诱导细胞凋亡。

The cytotoxicity and oxidative stress which was induced by selenite (SeIV) and selenomethionine (SeMet) in Caco-2 cells was investigated.Caco-2 cells were exposed to SeIV, SeMetat the difference dose for 24 h. At the same dose of SeIV and SeMet (0.8 μg Se/mL), the apoptosis of Caco-2 cells was detected by Annexin V-FITC/PI assay. The cell viability was evaluated by MTT assay. The leakage of lactate dehydrogenase (LDH), the activity of the superoxide dismutase (SOD), the glutathione (GSH) content were detected respectively. At the dose of 0.8 μg Se/mL, SeIV increased the apoptosis of Caco-2 cells (p<0.05), but there was no change in SeMet treatment. SeIV (≥0.4 μg Se/mL), SeMet (≥40 μg Se/mL) could all decrease the cell viability in a certain dose range (p<0.05) and as their exposure concentration increased, Caco-2 cell viability was gradually decreased. The IC50 values of Caco-2 cell exposed to SeIV and SeMet for 24 h were determined to be 2.56, 215.55 μg Se/mL, respectively. SeIV≥0.8 μg Se/mL and SeMet≥40 μg Se/mL showed the higher leakage of LDH than the control group 14.80% (p<0.05). SeIV≥4 μg Se/mL and SeMet≥4 μg Se/mL could decreased the SOD activity (56.76±3.64 U/mg prot) (p<0.05). SeIV≥4 μg Se/mL and SeMet (160 μg Se/mL) could decreased the GSH contents at the same time (61.67 μg/mg prot) (p<0.05). A certain concentration of SeIV and SeMet can induce oxidative stress in Caco-2 cells, leading to cytotoxicity and inducing apoptosis.

国家自然科学基金项目（41967048）；广西自然科学基金项目（2016GXNSFAA380308）；广西创新驱动重大专项（AA17202038）