Fig. 1

LCO particles induce MN in lung epithelial cells in vitro. Rat lung epithelial cells (RLE, 55556 cells/cm²) were exposed to culture medium (control, CTL), WC-Co, LCO or LTO, and cytotoxicity was assessed after 24 h by the WST-1 assay (a). The CBPI (b) was assessed in 500 cells exposed to non-cytotoxic particle concentrations, and the frequency of MN determined in 1000 binucleated cells (c). Image of a binucleated cell containing a micronucleus designated by the red arrow (c). *P < 0.05, **P < 0.01 and ***P < 0.001 relative to CTL cells (t-test or one-way ANOVA followed by a Dunnett’s multiple comparison). Bars represent means ± SEM (N = 2 for results obtained with 5 μg/ml LCO; N = 4 for all other results with n = 2 for CTL and n = 4 for all other conditions)