Fig. 5.
Uric acid increases superoxide production. (A) dHL-60 (1 × 106 cells) were incubated with 5 µM DHR, uric acid (0.2 or 0.5 mM) and PA14 (MOI 1:10) for 1 h. Oxidation of DHR was measured by fluorescence in a 96-well plate reader (λex = 500 nm, λem = 536 nm). (B) Kinetics of superoxide production in dHL-60 cells incubated with PA14 (MOI 1:10), uric acid (0.5 mM), DPI (20 μM) and DHE (10 μM) at 37 °C. Superoxide production was measured by 2-OH-E+ fluorescence (λex = 396 nm, λem = 579 nm). (C) Area under the curve (AUC) of total fluorescence up to 240 min. Each bar represents the mean ± SEM of three experiments. Statistical analyses were performed by one-way analyses of VARIANCE (ANOVA) followed by Newman-Keuls; *p < 0.05 and **p < 0.001 from control group (No PA14 in A or PA14 in C) and #p < 0.05 from PA14 + 0.5 mM UA. DPI: diphenyleneiodonium, UA: uric acid, A.U., arbitrary units.