Oridonin inhibits IL-1β-induced inflammation in human osteoarthritis chondrocytes by activating PPAR-γ

Osteoarthritis (OA), a progressive disease of the joints, affects millions of people worldwide. In the present study, we investigated the effects of oridonin, a diterpenoid isolated from Rabdosia rubescens, on IL-1 beta-induced inflammation using human osteoarthritis chondrocytes. The results showed that oridonin significantly suppressed IL-1 beta-induced MMP1, MMP3, and MMP13 production. IL-1 beta-induced NO and PGE(2) production, as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were also attenuated by oridonin. Western blot analysis demonstrated IL-1 beta-induced NF-kappa B activation was reduced by oridonin. Furthermore, the expression of PPAR-gamma was increased by oridonin in a concentration-dependent manner. PPAR-gamma antagonist could reverse the anti-inflammatory activity of oridonin. The results suggested that oridonin could be a candidate agent for the treatment of OA.