Figure 1

TNF-α production in quartz-incubated RAW 264.7 cells. (A) TNF-α concentration detected in RAW 264.7 cell supernatants after 6 hrs (black bars) and 18 hrs (white bars) stimulation with quartz, as determined using the L929 bio-assay. Cells were challenged with untreated (Q) or AA-treated (QA) quartz particles at 15, 50 and 100 μg/ml. Values are the mean ± SD from 4 experiments. The asterisks indicate a statistically significant difference between Q and QA values, at all particle concentrations at 6 h (T test, p < 0.0005). The symbols § indicate a statistically significant difference between Q and QA values at all particle concentrations, at 18 h (T test, p < 0.0005). (B) TNF-α concentration detected in RAW 264.7 cell supernatants after 6 h (black bars) and 18 hrs (white bars) stimulation with QA or Q particles in the presence of murine Interferon-γ (1 ng/ml). Values are the mean ± SD from 4 experiments. The asterisks indicate a statistically significant difference between Q and QA values at all particle concentrations, at 6 h (T test, p < 0.0005). The symbols § indicate a statistically significant difference between Q and QA values at all particle concentrations, at 18 h (T test, p < 0.0005). (C) TNF-α production in rat alveolar macrophages stimulated with 100 μg/ml QA or Q particles was evaluated after 6 h incubation. Values are the mean ± SD from 3 experiments. The asterisk indicates a statistically significant increase of TNF-α expression between Q100 and C samples (T Test, p < 0.0005), while the symbol § indicate a statistically significant difference between Q100 and QA100 TNF-α values (T Test, p < 0.0005).