中文摘要：

[目的] 研究纳米二氧化硅染毒对人肺腺癌A549细胞氧化应激与凋亡的影响。 [方法] 用质量浓度（后称“浓度”）为25、50、100、200 mg/L的纳米二氧化硅溶液染毒A549细胞，染毒时长为24、48 h，对照组不予处理。用荧光显微镜观察细胞形态变化；采用细胞计数试剂盒（cell counting kit，CCK-8）检测各组在各时间段的细胞存活率并计算出细胞抑制率与半数抑制浓度（IC50），绘制细胞抑制百分率曲线；用试剂盒检测各组细胞丙二醛（MDA）含量、超氧化物歧化酶（SOD）及乳酸脱氢酶（LDH）活性；采用流式细胞术检测各组细胞活性氧（ROS）含量和细胞凋亡率。[结果] 纳米二氧化硅染毒A549细胞24、48 h后，随着染毒浓度的升高，细胞形态发生改变，细胞出现皱缩、空泡。染毒24、48 h后，与对照组比较，各剂量组A549细胞抑制率均明显增加（P 〈 0.05），IC50分别为125.8、50.83 mg/L。染毒24、48 h后，与对照组相比，各浓度染毒组MDA含量、LDH活性随着染毒浓度的升高而升高（P 〈 0.05），而SOD活性随着染毒浓度升高呈下降趋势（P 〈 0.05）。ROS含量与凋亡率检测结果显示，与对照组相比，染毒24、48 h的染毒组中ROS与细胞凋亡率随着染毒浓度升高而升高，差异具有统计学意义（P 〈 0.05）。[结论] 纳米二氧化硅能够损伤A549细胞的细胞膜，产生氧化应激反应并刺激ROS的释放，引起细胞凋亡甚至死亡。

英文摘要：

Objective] To assess the effects of silica nanoparticles on oxidative damage and apoptosis in human lung adenocarcinoma A549 cells.[Methods] A549 cells were treated with silica nanoparticles at mass concentrations of 25, 50, 100, and 200 mg/L, respectively, for 24 and 48 h, and the control group was exposed to the culture media without silica nanoparticles. The morphologies of A549 cells after 24 and 48 h exposure were observed by fluorescence microscope. Cell viability was measured by cell counting kit （CCK-8）, cell inhibition rate and 50% inhibitory concentration （IC50） were calculated, and the curve of percentage of cell inhibition was also drawn. Malondialdehyde （MDA）, superoxide dismutase （SOD）, and lactate dehydrogenase （LDH） were detected by commercial kits. Flow cytometry was used to detect reactive oxidative species （ROS） and apoptosis rate.[Results] After being exposed to silica nanoparticles for 24 and 48 h, the A549 cells showed various morphological changes, including cell vacuolar degeneration and cell shrinkage. The cell inhibition rates were both increased after 24 and 48 h treatment compared with the control group （P 〈 0.05）. Moreover, the IC50 of the 24h exposure group was 125.8mg/L and that of the 48 h exposure group was 50.83 mg/L. The levels of MDA, LDH, ROS, and the apoptosis rates were higher in the groups exposed to higher doses of silica nanoparticles （P 〈 0.05） and the SOD levels showed in an inverse manner （P 〈 0.05）.[Conclusion] Silica nanoparticles could change cell morphology, aggregate oxidative stress, increase ROS, and even lead to cell apoptosis and death in A549 cells.