In vitro cellular responses to silicon carbide particles manufactured through the Acheson process: impact of physico-chemical features on pro-inflammatory and pro-oxidative effects.

Delphine Boudard (1, 2, 3) , Valérie Forest (2, 4) , Jérémie Pourchez (2, 4) , Najih Boumahdi (2, 5) , Maura Tomatis (6) , Bice Fubini (6) , Bernard Guilhot (2, 5) , Michèle Cottier (1, 2, 3) , Philippe Grosseau (2, 5)

1 LINA-ENSMSE - Laboratoire Interdisciplinaire d'Etude des Nanoparticules Aérosolisées
2 IFRESIS - Institut Fédératif de Recherche en Sciences et Ingénierie de la Santé
3 CHU ST-E - Centre Hospitalier Universitaire de Saint-Etienne [CHU Saint-Etienne]
4 CIS-ENSMSE - Centre Ingénierie et Santé
5 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
6 "G. Scansetti" Interdepartmental Center for Studies on Asbestos and other Toxic Particulates

Silicon carbide (SiC) an industrial-scale product manufactured through the Acheson process, is largely employed in various applications. Its toxicity has been poorly investigated. Our study aims at characterizing the physico-chemical features and the in vitro impact on biological activity of five manufactured SiC powders: two coarse powders (SiC C1/C2), two fine powders (SiC F1/F2) and a powder rich in iron impurities (SiC I). RAW 264.7 macrophages were exposed to the different SiC particles and the cellular responses were evaluated. Contrary to what happens with silica, no SiC cytotoxicity was observed but pro-oxidative and pro-inflammatory responses of variable intensity were evidenced. Oxidative stress (H₂O₂ production) appeared related to SiC particle size, while iron level regulated pro-inflammatory response (TNFα production). To investigate the impact of surface reactivity on the biological responses, coarse SiC C1 and fine SiC F1 powders were submitted to different thermal treatments (650 to 1400°C) in order to alter the oxidation state of the particle surface. At 1400°C a decrease in TNFα production and an increase in HO^., COO^.- radicals production were observed in correlation with the formation of a surface layer of crystalline silica. Finally, a strong correlation was observed between surface oxidation state and in vitro toxicity.

Mots clés: silicon carbide powders; Acheson process; thermal post-treatment; physico-chemical characterization; biological toxicity; occupational exposure.; occupational exposure

Domaines: Génie des procédés; Toxicologie et chaîne alimentaire

Delphine Boudard, Valérie Forest, Jérémie Pourchez, Najih Boumahdi, Maura Tomatis, et al.. In vitro cellular responses to silicon carbide particles manufactured through the Acheson process: impact of physico-chemical features on pro-inflammatory and pro-oxidative effects.. Toxicology in Vitro, 2014, 28 (5), pp.856-865. ⟨10.1016/j.tiv.2014.02.012⟩. ⟨hal-01021766⟩