Effects of sodium ferulate on cycloxygenase-2, prostaglandin E2, inducible nitric oxide synthase, and nitric oxide. Effects of sodium ferulate (SF) on cycloxygenase-2 (COX-2), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS) and nitric oxide (NO) expression and synthesis of rat osteoarthritis (OA) chondrocytes induced by IL-1β. (a) Effects of SF on protein expression of COX-2 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in rat OA chondrocytes. Chondrocytes were incubated with SF alone for 24 hours, and then co-treated with IL-1β and SF for 48 hours. Expression of COX-2 and GAPDH determined by western blotting. (b) Effects of SF on gene expression of iNOS and GAPDH in rat OA chondrocytes. Level of iNOS was evaluated by real-time quantitative PCR. (c) Effects of SF on NO synthesis of rat OA chondrocytes induced by IL-1β. NO production was measured as nitrite (NO2-) in the culture medium by the Griess reaction. NO concentration was calculated (expressed in μmol/l). (d) Effects of SF on expression of PGE2 in rat OA chondrocytes. The release of PGE2 was analyzed by ELISA and the concentration was calculated (expressed in pg/ml). Values represent mean ± standard error of the mean of three different simples. **P < 0.01 versus normal control. ##P < 0.01 versus OA model control.