Figure 3

ROS and TNF-α production in quartz-stimulated cells in the presence of ROS scavengers. (A) Fluorimetric measurement of ROS production in RAW 264.7 macrophages challenged with 15, 50 and 100 μg/ml Q or QA particles. Values are the mean ± SD from 4 experiments. The symbol § indicates a statistically significant difference of QA-challenged cells compared to control, untreated cells (C), (T test, p < 0.0005); the asterisk indicates a statistically significant difference of Q-challenged cells compared to C (T test, p < 0.0005). (B) TNF-α production was evaluated in RAW 264.7 cells after 6 hrs incubation with 100 μg/ml Q or QA particles (black bars: Q samples; white bars: QA samples) in the presence of 4000 U/ml catalase (Qc, QAc bars), 50 mM mannitol (Qm, QAm bars) and 2 mM desferoxamine (Qd, QAd bars). Values are the mean ± SD from 4 experiments. The symbol § indicates a statistically significant difference between Q and Qc bars and between QA and QAc bars (T test, p < 0.0005). The asterisks indicate a statistically significant difference between Q and Qm, and between QA and QAm bars (T test, p < 0.0005).