title: PVP-coated silver nanoparticles and silver ions induce reactive oxygen species, apoptosis and necrosis in THP-1 monocytes.
abstract: The objective of the present study was to investigate the toxicity of silver nanoparticles (Ag NPs) in vitro. Silver ions (Ag+) have been used in medical treatments for decades whereas Ag NPs have been used in a variety of consumer products within recent years. This study was undertaken to compare the effect of well characterized, PVP-coated Ag NPs (69 nm +/- 3 nm) and Ag+ in a human monocytic cell line (THP-1). Characterization of the Ag NPs was conducted in both stock suspension and cell media with or without serum and antibiotics. By using the flowcytometric annexin V/propidium iodide (PI) assay, both Ag NPs and Ag+ were shown to induce apoptosis and necrosis in THP-1 cells depending on dose and exposure time. Furthermore, the presence of apoptosis could be confirmed by the TUNEL method. A number of studies have implicated the production of reactive oxygen species (ROS) in cytotoxicity mediated by NPs. We used the fluorogenic probe, 2',7'-dichlorofluorescein to assess the levels of intracellular ROS during exposure to Ag NPs and Ag+. A drastic increase in ROS levels could be detected after 6-24h suggesting that oxidative stress is an important mediator of cytotoxicity caused by Ag NPs and Ag+.
authors.affiliation: Department of Environmental and Occupational Medicine, Institute of Public Health, Aarhus University, Bartholins Allé 2, Bygn. 1260, 8000 Aarhus, Denmark. rfol@mil.au.dk
authors.forename: Rasmus
authors.initials: R
authors.lastname: Foldbjerg
authors.forename: Ping
authors.initials: P
authors.lastname: Olesen
authors.forename: Mads
authors.initials: M
authors.lastname: Hougaard
authors.forename: Duy Anh
authors.initials: DA
authors.lastname: Dang
authors.forename: Hans Jürgen
authors.initials: HJ
authors.lastname: Hoffmann
authors.forename: Herman
authors.initials: H
authors.lastname: Autrup
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D006801:Humans; D020287:In Situ Nick-End Labeling; D008027:Light; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D053758:Nanoparticles; D009336:Necrosis / Q000473:pathology; D010316:Particle Size; D011143:Polyvinyl Chloride / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012542:Scattering, Radiation; D012834:Silver / Q000494:pharmacology*
chemical_list: D017304:Annexin A5; D005456:Fluorescent Dyes; D017382:Reactive Oxygen Species; D012834:Silver; D011143:Polyvinyl Chloride