Figure 6

TNF-α production and cell viability in quartz-stimulated cells in the presence of DXS. (A) TNF-α production in cell supernatants after 6 h incubation with 100 μg/ml Q or QA (white bars) particles in the presence or absence of 100 μg/ml DXS (Q+D, QA+D), and of 500 μg/ml BHT (Q+D+B, QA+D+B). Values are the mean ± SD from 4 experiments. The symbol # indicates a statistically significant difference between Q and QA challenged cells (T test, p < 0.0005); the asterisk indicates a statistically significant difference between Q and Q+D challenged cells (T test, p < 0.0005), while the symbol § indicates a statistically significant difference between QA and QA+D treated cells (T test, p < 0.0005). (B) RAW 264.7 cell viability after 24 h incubation with 100 μg/ml Q or QA (white bars) particles in the presence or absence of 100 μg/ml DXS (Q+D, QA+D), and of 500 μg/ml BHT (Q+D+B, QA+D+B). Values are the mean ± SD from 4 experiments. The symbol # indicates a statistically significant difference between control, untreated cells (C) and Q and between C and QA (T test, p < 0.0005); the asterisk indicates a statistically significant difference between Q and Q+D challenged cells (T test, p < 0.0005), while the symbol § indicates a statistically significant difference between QA and QA+D treated cells (T test, p < 0.0005). (C) Percentage of RAW 264.7 cell death (measured by Sytox Green DNA assay, see Methods) and apoptosis (measured by FACS analysis of phosphatidylserine-positive cells, see Methods) after 24 h incubation with 100 μg/ml Q or QA particles in the presence or absence of 100 μg/ml DXS (Q+D, QA+D), and of 500 μg/ml BHT (Q+D+B, QA+D+B). Values are the mean ± SD from 3 experiments.