title: Combined exposure to nano-silica and lead induced potentiation of oxidative stress and DNA damage in human lung epithelial cells.
abstract: Growing evidence has confirmed that exposure to ambient particulate matters (PM) is associated with increased morbidity and mortality of cardiovascular and pulmonary diseases. Ambient PM is a complex mixture of particles and air pollutants. Harmful effects of PM are specifically associated with ultrafine particles (UFPs) that can adsorb high concentrations of toxic air pollutants and are easily inhaled into the lungs. However, combined effects of UFPs and air pollutants on human health remain unclear. In the present study, we elucidated the combined toxicity of silica nanoparticles (nano-SiO2), a typical UFP, and lead acetate (Pb), a typical air pollutant. Lung adenocarcinoma A549 cells were exposed to nano-SiO2 and Pb alone or their combination, and their combined toxicity was investigated by focusing on cellular oxidative stress and DNA damage. Factorial analyses were performed to determine the potential interactions between nano-SiO2 and Pb. Our results showed that exposure of A549 cells to a modest cytotoxic concentration of Pb alone induced oxidative stress, as evidenced by elevated reactive oxygen species generation and lipid peroxidation, and reduced glutathione content and superoxide dismutase and glutathione peroxidase activities. In addition, exposure of A549 cells to Pb alone induced DNA damage, as evaluated by alkaline comet assay. Exposure of A549 cells to non-cytotoxic concentration of nano-SiO2 did not induce cellular oxidative stress and DNA damage. However, exposure to the combination of nano-SiO2 and Pb potentiated oxidative stress and DNA damage in A549 cells. Factorial analyses indicated that the potentiation of combined toxicity of nano-SiO2 and Pb was induced by additive or synergistic interactions.
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China; Department of Pharmacology, Basic Medical College, Jiamusi University, Jiamusi 154007, PR China.
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Lu
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Yuan
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China.
authors.forename: Li-Zhong
authors.initials: LZ
authors.lastname: Li
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China. Electronic address: wangyimei2006@126.com.
authors.forename: Yi-Mei
authors.initials: YM
authors.lastname: Wang
authors.affiliation: Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, 20 Dongdajie Street, Fengtai District, Beijing 100071, PR China. Electronic address: pengsq@hotmail.com.
authors.forename: Shuang-Qing
authors.initials: SQ
authors.lastname: Peng
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000975:Antioxidants / Q000032:analysis; D002460:Cell Line; D020552:Comet Assay; D004249:DNA Damage; D004357:Drug Synergism; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D007854:Lead / Q000032:analysis / Q000633:toxicity*; D015227:Lipid Peroxidation / Q000187:drug effects; D008168:Lung / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D053758:Nanoparticles / Q000032:analysis / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000032:analysis; D012822:Silicon Dioxide / Q000032:analysis / Q000633:toxicity*; D013499:Surface Properties
chemical_list: D000393:Air Pollutants; D000975:Antioxidants; D052638:Particulate Matter; D017382:Reactive Oxygen Species; D007854:Lead; D012822:Silicon Dioxide
keywords: Combined toxicity; DNA damage; Nano-SiO(2); Oxidative stress; PM; Pb