Micronucleus formation in V79 cells treated with respirable silica dispersed in medium and in simulated pulmonary surfactant.
Liu-X; Keane-MJ; Zhong-B-Z; Ong-T-M; Wallace-WE
Mutat Res 1996 Dec; 361(2-3):89-94
Dipalmitoylphosphatidylcholine (DPPC) was used to model pulmonary surfactant in-vitro. The micronucleus (MN) formation test was used to study the genotoxicity of native and surfactant coated quartz in Chinese-hamster lung fibroblasts (V79 cells). V79 cells were challenged with two particle sizes of crystalline silica (14808607) and a noncrystalline silica. In the second part, two DPPC coated crystalline silicas were incubated with V79 cells for various exposure times to study the effect of surfactant on the quartz induced MN formation. The two native crystalline silica samples and the one native amorphous silica (60676860) sample induced MN formation in V79 cells, while high cytotoxicity was observed at the inducing concentrations. The MN frequencies were significantly elevated over their respective solvent controls in a dose dependent manner. The DPPC coated particle failed to induce MN formation at all concentrations when compared to the uncoated particles. Less cytotoxicity was noted for the DPPC treated particles relative to the untreated silica particles. Studies of possible genotoxic properties of DPPC coated silica particles with prolonged treatment indicated that no increased MN formation was found in V79 cells with medium changes on the second and fourth days. However, all of the 5 day treatment groups incurred a significant increase in MN frequencies over their respective 1 day treatment groups.
Cell-cultures; Cytotoxic-effects; Genotoxic-effects; Lung-cells; Silica-dusts; Mineral-dusts; Mammalian-cells; In-vitro-studies;
Author Keywords: Silicon dioxide; Quartz; V79 lung fibroblast; Micronucleus induction; Pulmonary surfactant; Dipalmitoylphosphatidylcholine
Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505-2888, USA