Echinocystic Acid Inhibits IL-1β-Induced COX-2 and iNOS Expression in Human Osteoarthritis Chondrocytes

Echinocystic acid (EA), a pentacyclic triterpene isolated from the fruits of Gleditsia sinensis Lam, displays a range of pharmacological activities including anti-inflammatory and antioxidant effects. However, the effect of EA on IL-1β-stimulated osteoarthritis chondrocyte has not been reported. The purpose of this study was to assess the effects of EA on IL-1β-stimulated human osteoarthritis chondrocyte. Chondrocytes were stimulated with IL-1β in the absence or presence of EA. NO and PGE2 production were measured by Griess reagent and ELISA. The expression of COX-2, iNOS, nuclear factor-κB (NF-κB), inhibitory kappa B (IκBα), c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK) were detected by Western blot analysis. The results showed that EA suppressed IL-1β-induced collagenase-3 (MMP-13), NO, and PGE2 production in a dose-dependent manner. IL-1β up-regulated the expression of COX-2 and iNOS, and the increase was inhibited by EA. Furthermore, IL-1β-induced NF-κB and mitogen-activated protein kinase (MAPK) activation were inhibited by EA. In conclusion, EA effectively attenuated IL-1β-induced inflammatory response in osteoarthritis chondrocyte which suggesting that EA may be a potential agent in the treatment of osteoarthritis.

Taraxasterol inhibits IL-1β-induced inflammatory response in human osteoarthritic chondrocytes

Osteoarthritis (OA), a chronic degenerative joint disease, is a leading cause of disability among elderly patients. Taraxasterol, a pentacyclic-triterpene isolated from Taraxacum officinale, has been shown to have anti-inflammatory effects. However, the protective effect of taraxasterol on OA remains unclear. In order to provide a scientific basis for the applicability of taraxasterol in OA, the anti-inflammatory effects of taraxasterol on IL-1β-stimulated osteoarthritic chondrocytes were investigated. Chondrocytes were pretreated with taraxasterol 1h before IL-1β treatment. The productions of MMP-1, MMP3, MMP13, PGE2 and NO were measured by ELISA and Griess reaction. The expression of COX-2, iNOS, and NF-κB was detected by western blot analysis. Our results demonstrated that taraxasterol dose-dependently suppressed MMP-1, MMP3, MMP13, PGE2 and NO production induced by IL-1β. The expression of COX-2 and iNOS was also inhibited by taraxasterol. Western blot analysis showed that taraxasterol suppressed IL-1β-induced NF-κB activation in a dose-dependent manner. Taken together, we found that taraxasterol protected human chondrocytes by inhibiting MMPs, NO and PGE2 production. Taraxasterol may be a useful agent for prevention and treatment of OA.