中文摘要：

目的研究氧化铈（CeO2）纳米颗粒对过氧化氢所致A549细胞损伤的保护作用。方法采用扫描电子显微镜（SEM）、X射线粉末衍射仪（XRD）和纳米粒度及Zeta电位分析仪对纳米CeO2的理化性质进行表征，A549细胞暴露于0-40μg／mlCeO2纳米颗粒悬液（粒径约为30nm）24和48h，以MTT方法检测CeO2纳米颗粒对细胞活性的影响、纳米CeO2缓解20μmol／LH2O2对A549细胞造成氧化损伤的能力以及对细胞内SOD活力和GSH含量变化的影响，以流式细胞术检测CeO2纳米颗粒对细胞凋亡率的影响及细胞对纳米颗粒的摄取情况。结果5～40μg／mlCeO2纳米颗粒对细胞活性均呈现促进作用，作用时间为48h，浓度为20和40μg／ml时细胞存活率分别为111．66％和113．04％，与对照组相比，差异有统计学意义（P〈0．05）。20和40μg／ml纳米CeO2＋H2O2组细胞存活率与单独H2O2染毒组相比分别增加10．21％和16．54％，细胞内SOD活力与单独H2O2染毒组相比分别增加46．23％和61．87％，GSH含量与单独H2O2染毒组相比分别增加21．98％和45．86％。CeO2纳米颗粒可以进入到A549细胞内部，细胞总凋亡率与H2O2组相比下降10．33％。结论CeO2纳米颗粒可以缓解H2O2对A549细胞造成的氧化损伤，对细胞起到保护作用。

英文摘要：

Objective To observe the protective effects of cerium oxide （CeO2） nanoparticles on oxidative damage induced by hydrogen peroxide （H2O2） in human lung adenocarcinoma cell line （A549） in vitro. Methods The physical and chemical properties of CeO2 nanoparticles were characterized by scanning electron microscopy （SEM）, X-ray powder diffraction （XRD） and nano-particle size and zeta potential analyzer. The cell viability of A549 exposed to 0-40 μg/ml CeO2 nanoparticles for 24 and 48 h was evaluated by 3-（4,5-dimethyhhiazol）-2,5-diphenltetrazoliumh romide （MTr） assay. The ability of scavenging reactive oxygen radicals, intracellular SOD activity and GSH content were assessed by microplate reader. The cellular uptake of CeO2 nanoparticles and rate of apoptosis were systematic studied by flow cytometry. Results CeO2 nanoparticles promoted the viability of A549 cells. After cells were exposed to CeO2 nanoparticles at 20 and 40 μg/ml for 48 h, cell viability increased to 111.66 % and 113.04% compared with the control group. CeO2 nanoparticles could decrease oxidative damage induced by H2O2 through scavenging reactive oxygen free radicals. After cells were exposed to CeO2 nanoparticles at 20 and 40 μg/ml, cell viability increased by 10.21% and 16.54%, SOD activity in cells increased by 46.23% and 61.87%, GSH content in cells increased by 21.98% and 45.86%, respectively, compared with the H2O2 group. CeO2 nanoparticles could enter cells and reduce the apoptosis rate induced by H2O2 by 10.33%. Conclusion CeO2 nanoparticles can alleviate oxidative damage caused by external stimuli and present a protective effect to cells.