Effect of uric acid on GSH and GSSG levels. dHL-60 cells (5 × 106) were incubated with uric acid (UA, 0.2 or 0.5 mM) and challenged with PA14 (MOI 1:10). Samples were injected onto LC/MS/MS and the mass transitions (m/z 308.0911 → 179.0462) and (m/z 613.1592 → 355.0741) for GSH and GSSG, respectively, were monitored. Each bar represents the mean ± SEM of three independent experiments. Statistical analysis were performed by one-way ANOVA analysis of VARIANCE, followed by Newman-Keuls post-hoc test, *p < 0.05 compared to control without PA14.