中文摘要：

目的：研究纳米银对人肺癌（A549）和人肝癌（HepG2）细胞系增殖和凋亡的影响,并探讨纳米银对两种细胞系毒效应的差异及其机制。方法：用20、40、80、160、320、640μg/mL的纳米银分别染毒A549和HepG2细胞,染毒时长均为24和48 h,以细胞培养液为对照,采用MTT法检测各组细胞的存活率;谷胱甘肽（GSH）和超氧化物歧化酶（SOD）试剂盒检测细胞内GSH含量和SOD活力。除上述各染毒组,两种细胞均另设置N-乙酰半胱氨酸（NAC）预处理后160μg/mL纳米银染毒组,采用流式细胞术检测各组细胞凋亡率。结果：与对照组比较,染毒24和48 h后,≥40μg/mL剂量组A549细胞和所有剂量组HepG2细胞存活率均降低（P〈0.05或P〈0.01）;与相同染毒条件下的A549细胞比较,40~640μg/mL剂量组HepG2细胞的存活率较高（P〈0.05或（P〈0.01）。SOD活力和GSH含量检测发现,纳米银染毒A549细胞24 h后,40 pg/mL剂量组SOD活力与对照组比较显著降低（P〈0.05）,而GSH含量上升（P〈0.05）;染毒48 h后,SOD活力和GSH含量在40~160μg/mL剂量组下降,其中80μg/mL剂量组GSH含量与对照组间的差异显著（P〈0.05）。纳米银染毒HepG2细胞24、48 h后,SOD活力和GSH含量都表现为上升,其中40、80μg/mL组SOD活力和20μg/mL组GSH含量与对照组间的差异显著（P〈0.05）。细胞凋亡率检测发现,染毒24 h时,各剂量组A549细胞凋亡率与对照组比较差异无统计学意义（P〉0.05）,而各剂量组HepG2细胞凋亡率均显著增加（P〈0.05或P〈0.01）;染毒48 h时,≥40μg/mL剂量组A549细胞和160μg/mL剂量组HepG2细胞凋亡率均高于对照组（P〈0.05或P〈0.01）。使用NAC预处理细胞后,160μg/mL剂量组两种细胞系凋亡率均显著下降（P〈0.01）。结论：纳米银可以引起A549和HepG2细胞表现不同程度的增殖抑制和凋亡,而细胞内不同的SOD和GSH改变可能是纳米银引起两种细胞系不同毒作用的原因之一。

英文摘要：

OBJECTIVE：To study the effect of silver nanoparticles（AgNPs） on proliferation and apoptosis of human lung cancer（A549） and hepatoma cells（HepG2）.To discuss the potential reasons for different toxicity of AgNPs in the two cell lines.METHODS：A549 and HepG2 cells were treated with AgNPs at concentrations of 20,40,80,160,320,640 μg/mL,respectively for 24 and 48 h.Control cultures did not receive treatment.Cell viability was measured by the MTT assay,and glutathione（GSH） and superoxide dismutase（SOD） detection kit were used to determine the level of GSH and SOD.In addition,some cultures were pretreated with N-acetylcysteine（NAC） prior to incubating with 160 μg/mL AgNPs.Flow cytometry was used to detect apoptotic rates for all cell culture groups.RESULTS：After 24 or 48 h of treatment with all dose groups,the survival rates of A549（except for 20 μg/mL group） and HepG2 cells were significantly lower than that in the control group（P〈0.05 or P〈0.01）.However,the rates of HepG2 cells which were treated with 40-640 μg/mL AgNPs were significantly higher than that of A549 cells（P〈0.05 or P〈0.01）.After 24 h of treatment,the SOD activity of A549 cells which were treated with 40 μg/mL AgNPs group was significantly lower than that of the control group（P〈0.05）,while the GSH levels of A549 cells which were treated with all dose groups were higher.After 48 h of treatment,SOD activity and GSH levels decreased in the 40-160 μg/mL treatment groups.After 24 or 48 h of treatment,SOD activity and GSH levels were increased in HepG2 cells.After 24 h of treatment,the apoptosis rates of HepG2 cells were significantly higher than that of the control group（P〈0.05 or P〈0.01）,while the apoptosis rate of A549 cells had not changed significantly（P〉0.05）.After 48 h of treatment,the apoptosis rate of A549 cells（except for 20 μg/mL group） and HepG2 cells（160 μg/mL group） were significantly higher than that of the control group（P〈0.05 or P〈0.01）.However,the apop