title: Exposure of the murine RAW 264.7 macrophage cell line to hydroxyapatite dispersions of various composition and morphology: assessment of cytotoxicity, activation and stress response.
abstract: Cellular stress responses leading to the release of cytotoxic mediators are discussed as indicators of the hazard presented by particles, and in particular ultrafine particles or nanomaterials. The present study was designed to investigate effects of the following materials on RAW 264.7 macrophages: three hydroxyapatite materials of various morphologies, i.e., nano-sized with rod-like (HA-NR), plate-like (HA-NP) or needle-shaped (HA-NN) morphology, and an irregularly shaped composite of hydroxyapatite and protein (HPC) in the low micrometer range. Concentrations of 50, 100, 500, 1000 and 5000 microg/ml were applied and cells were analyzed for viability (XTT-test), cytokine production (TNF-alpha) and induction of nitric oxide (NO) after 18 and 42 h. DQ12 quartz and lipopolysaccharide (LPS) served as positive controls. Up to concentrations of 500 microg/ml, cell viability was not considerably impaired by the test samples at both timepoints. Overall, viability was about one order of magnitude higher than with comparable concentrations of quartz. TNF-alpha release was induced in all samples after 18 h, with HA-NR showing the most pronounced induction at 100 microg/ml, still clearly below the LPS signal. No or little induction was observed after 42 h. NO production was low after 18 and 42 h. The results support the conclusion that the tested materials exhibit good biocompatibility and are safe to use.
authors.affiliation: Laboratorium für Toxikologie und Okologie (LTO), Evonik Stockhausen GmbH, 47805 Krefeld, Germany. julia.scheel@henkel.com
authors.forename: Julia
authors.initials: J
authors.lastname: Scheel
authors.forename: Sabine
authors.initials: S
authors.lastname: Weimans
authors.forename: Astrid
authors.initials: A
authors.lastname: Thiemann
authors.forename: Eckhard
authors.initials: E
authors.lastname: Heisler
authors.forename: Martina
authors.initials: M
authors.lastname: Hermann
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D006882:Hydroxyapatites / Q000633:toxicity*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008422:Materials Testing; D051379:Mice; D053758:Nanoparticles / Q000633:toxicity*; D009569:Nitric Oxide / Q000096:biosynthesis; D018384:Oxidative Stress / Q000187:drug effects*; D010316:Particle Size; D011791:Quartz / Q000633:toxicity
chemical_list: D016207:Cytokines; D006882:Hydroxyapatites; D008070:Lipopolysaccharides; D011791:Quartz; D009569:Nitric Oxide