Figure 1

Time- and concentration-dependent DEP-induced and concentration-dependent SRM1650a-induced cytotoxicity. Human bronchial epithelial BEAS-2B cells were exposed to increasing concentrations of DEPs (0-400 μg/ml) for 2, 4, 6 or 24 h, before they were stained with Hoechst 33342 and PI and analysed by fluorescence microscopy. SRM1650a served as a reference sample (0-400 μg/ml) for cytotoxicity induced after 24 h of exposure. Bars represent means ± SEM of the percentage of PI-positive cells counted in separate experiments (n = 3). * p < 0.05; exposed vs. unexposed cells at each investigated timepoint.