PVP-coated silver nanoparticles and silver ions induce reactive oxygen species, apoptosis and necrosis in THP-1 monocytes

• Published in: Toxicology letters Vol. 190; no. 2; pp. 156 - 162
• Main Authors: Foldbjerg, Rasmus, Olesen, Ping, Hougaard, Mads, Dang, Duy Anh, Hoffmann, Hans Jürgen, Autrup, Herman
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 28.10.2009; Elsevier
• Subjects: Annexin A5 - metabolism; Apoptosis; Apoptosis - drug effects; Biological and medical sciences; Cell Line, Tumor; Chemical and industrial products toxicology. Toxic occupational diseases; Flow Cytometry; Fluorescent Dyes; Humans; In Situ Nick-End Labeling; Light; Medical sciences; Metals and various inorganic compounds; Monocytes; Monocytes - drug effects; Monocytes - metabolism; Monocytes - pathology; Nanoparticles; Necrosis - pathology; Particle Size; Polyvinyl Chloride - pharmacology; Reactive oxygen species; Reactive Oxygen Species - metabolism; Scattering, Radiation; Silver; Silver - pharmacology; Toxicology; Nanoparticles; Silver; Reactive oxygen species; Monocytes; Apoptosis; Human; Oxidative stress; Monocyte; Nanoparticle; Ions; Transition metal; Ultrafine particle; Necrosis; Cell line; Pyrrolidone(vinyl) polymer; Cell death
• ISSN: 0378-4274; 1879-3169
• DOI: 10.1016/j.toxlet.2009.07.009

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 6–24 h suggesting that oxidative stress is an important mediator of cytotoxicity caused by Ag NPs and Ag+.