Fig. 2

Effect of mitogen-activated protein kinase (MAPK) inhibitors on lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) production, nitrite accumulation, and inducible nitric oxide synthase (iNOS) expression. Cultured cells were treated with various concentrations (10 and 20 μM) of SB203580 (a p38 inhibitor), PD98059 (an extracellular signal-regulated kinase (ERK) inhibitor), or SP600125 (a c-Jun N-terminal kinase (JNK) inhibitor), and then exposed to LPS (100 ng/ml) for 24 h. a ROS production by cells was detected by DCF fluorescence. The y-axis of the graph is expressed in DCF fluorescent arbitrary units (AU). b The culture medium was collected to analyze levels of nitrite accumulation. c After treatment, cells were harvested for a Western blot analysis. Levels of iNOS were normalized to β-actin, and then quantified. The iNOS expression induced by LPS was set to 100 % expression. Data are expressed as the mean ± SEM (n = 4 or 5 in each group). ***p < 0.001 vs. the control (Cont.); ⁺ p < 0.05, ⁺⁺ p < 0.01, ⁺⁺⁺ p < 0.001 vs. LPS