Abstract
[Display omitted]
•Catalpol is an iridoid glucoside isolated from Rehmannia glutinosa Libosch.•Catalpol alleviated collagen II-induced arthritis in rats.•Catalpol inhibited LPS-induced inflammatory response in SW982 cells.•Catalpol suppressed LPS-induced MAPK, NF-κB and AP-1 pathways in SW982 cells.
Catalpol, an effective component of China's functional food Rehmannia glutinosa Libosch, has a wide range of pharmacological effects. However, it is unclear whether catalpol exhibits protective and therapeutic potential against rheumatoid arthritis. In this study, the effects of catalpol in rats with collagen II-induced arthritis (CIA) and in LPS-stimulated SW982 human synovial cells were investigated. Catalpol significantly reduced paw swelling and thickness in rats with CIA. Histopathology revealed that catalpol alleviated articular cartilage damage, infiltration of inflammatory cells and synovial hyperplasia. Catalpol also inhibited protein and mRNA levels of IL-6, IL-8 and MMP-1, and the expression of COX-2 and mPGEs-1 in LPS-stimulated SW982 cells. Furthermore, the phosphorylation levels of ERK, JNK, p65, IκBα and c-Jun were suppressed by catalpol. Taken together, these findings showed that catalpol had inhibitory effects against arthritis, which may be related to decreased production of pro-inflammatory mediators and suppression of the MAPK, NF-κB and AP-1 pathways.