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[目的]研究纳米二氧化硅(nano-SiO2)对人肺腺癌A549细胞的毒性作用.[方法]将A549细胞随机分成6组,即对照组和实验组(5、10、25、50、100 mg/L nano-SiO2组).实验组分别用不同浓度的nano-SiO2(10～20 nm粒径)刺激,MTT法检测细胞活性,比色法测定乳酸脱氢酶(LDH)活性,透射电子显微镜观察细胞微观结构,流式细胞仪检测nano-SiO2对细胞周期以及细胞凋亡的影响.[结果]与对照组相比:随着nano-SiO2浓度升高,A549细胞存活率呈降低趋势;LDH活性增加(P＜0.01或P＜0.05),在浓度为0、5、10、25 mg/L时呈浓度依赖关系,但在nano-SiO2浓度为50mg/L时,LDH活力降低,100 mg/L时增高.nano-SiO2浓度的升高可导致细胞膜表面绒毛凸起减少,细胞器空泡样变增加,次级溶酶体增多;细胞凋亡率增加,坏死率增加;细胞在G0/G1期阻滞,增殖受抑制.[结论] nano-SiO2作用于A549细胞可被细胞摄取,使细胞器结构功能受损,从而抑制细胞增殖、诱导细胞凋亡,引起细胞周期紊乱.“,”[Objective] To study the toxic effects of SiO2 nanoparticles (nano-SiO2) on human pulmonary adenocarcinoma A549 cells.[Methods] Different concentrations of nano-SiO2 (10-20nm) (5,10,25,50,and 100mg/L) were evaluated for their potential toxicity in A549 cells.Cell viability was determined by MTT assay,lactate dehydrogenase (LDH) activity by colorimetric analysis method,microstructure of organelle by transmission electron microscope,and apoptosis and cell cycle by flow cytometry.[Results] Compared with the control group,exposure to increasing concentrations of nano-SiO2 resulted in a diminishing viability of A549 cells.The activity of LDH increased in a dose-dependent manner with nano-SiO2 from 0 to 25 mg/L (P＜0.01 or P＜ 0.05),decreased at 50mg/L nano-SiO2,and then increased at 100 mg/L nano-SiO2.With the increase of nano-SiO2 concentrations,cell membrane villi decreased;organell cavity changes increased;secondary lysosomes increased;more cell apoptosis or necrosis appeared;A549 cells were arrested at G0/G1 phase and proliferation was inhibited.[Conclusion] Nano-SiO2 can be uptaken by A549 cells,resulting in impaired organelle structure and function,thus inhibiting cell proliferation,inducing cell apoptosis,and causing cell cyclical disorders.