Tomatidine inhibits IL-1β-induced iNOS and COX-2 expression in primary chondrocytes. (A) Representative western blot images and (B) Histogram plots show the levels of iNOS and COX-2 proteins relative to GAPDH (internal control) levels in primary chondrocytes treated for 24 h with 2.5, 5, or 10μM tomatidine alone or in combination with 10ng/mlIL-1β. DMSO was used as control. The values are shown as means ± SD of triplicate experiments. #p < 0.05 compared with the control group; *p < 0.05 and **p < 0.01 compared with the IL-1β group.