FIG. 6.

NADPH oxidase inhibitors blocked ROI production induced by IL-1β stimulation in monocytic cells. Formation of ROIs was measured by using a DFCH probe in U937 (A), THP-1 (B), and Raji (C) cells after IL-1β stimulation, with and without preincubation in the presence of the NADPH oxidase inhibitors DPI and PAO. Columns 1, background (no DFCH probe); columns 2, unstimulated cells; columns 3, stimulation with IL-1β (50 U/ml); columns 4, as in columns 3 plus PAO (30 μg/ml); columns 5, as in columns 3 plus PAO (60 μg/ml); columns 7, stimulation with IL-1β (50 U/ml); columns 8, as in columns 7 plus DPI (10 μM); columns 9, as in columns 7 plus DPI (30 μM); columns 6 and 10, stimulation with H₂O₂ (250 μM). Asterisks indicate that values are statistically different from the reference values (Δ).