Cytotoxicity and inflammation in human alveolar epithelial cells following exposure to occupational levels of gold and silver nanoparticles
While inhalation represents one of the most likely routes of exposure, the toxicity and response of nanoparticles at concentrations expected from such an exposure are not well understood. Here we characterized the in vitro response of human A549 adenocarcinomic alveolar epithelial cells following exposure to gold (AuNP) and silver (AgNP) nanoparticles at levels approximating an occupational exposure. Changes in neither oxidative stress nor cytotoxicity were significantly affected by exposure to AgNPs and AuNPs, regardless of NP type (Ag vs. Au), concentration, surface ligand (citrate or tannic acid), or size. An inflammatory response was, however, observed in response to 20 nm AgNPs and 20 nm AuNPs, where significant differences in the release of interleukin (IL)-8 but not IL-6 were observed. Additional data demonstrated that increased IL-8 secretion was strongly dependent on both nanoparticle size and concentration. Overall these data suggest that, while not acutely toxic, occupational exposure to AuNPs and AgNPs may trigger a significant inflammatory response in alveolar epithelium. Moreover, the differential responses in IL-8 and IL-6 secretion suggest that NPs may induce a response pathway that is distinct from those commonly elicited by allergens and pathogens.
KeywordsNanotoxicology Occupational health Toxicology Particle toxicology
The authors would like to thank Drs. Nathan Bouxsein and Conrad James for their critical comments on this manuscript. This work was supported by Sandia National Laboratories’ Laboratory Directed Research and Development Office, and was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
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