Combined exposure to nano-silica and lead induced potentiation of oxidative stress and DNA damage in human lung epithelial cells

• Published in: Ecotoxicology and environmental safety 2015-12, Vol.122, p.537-544
• Main Authors: Lu, Chun-Feng, Yuan, Xiao-Yan, Li, Li-Zhong, Zhou, Wei, Zhao, Jun, Wang, Yi-Mei, Peng, Shuang-Qing
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Air Pollutants - toxicity; Antioxidants - analysis; Cell Line; Combined toxicity; Comet Assay; Damage; Deoxyribonucleic acid; DNA Damage; Drug Synergism; Epithelial Cells - drug effects; Epithelial Cells - enzymology; Epithelial Cells - pathology; Exposure; Humans; Lead (metal); Lead - analysis; Lead - toxicity; Lipid Peroxidation - drug effects; Lung - drug effects; Lung - enzymology; Lung - pathology; Nano-SiO2; Nanoparticles - analysis; Nanoparticles - toxicity; Nanostructure; Oxidative stress; Oxidative Stress - drug effects; Particle Size; Particulate Matter - analysis; Particulate Matter - toxicity; Pollutants; Reactive Oxygen Species - analysis; Silicon Dioxide - analysis; Silicon Dioxide - toxicity; Stresses; Surface Properties; Toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2015.09.030

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. •Exposure to Pb alone induced oxidative stress and DNA damage in A549 cells.•Non-cytotoxic concentration of nano-SiO2 exacerbated Pb-induced oxidative toxicity.•Potentiated combined toxicity was induced by additive or synergistic interaction.