Inhibition effect of Caragana sinica root extracts on Osteoarthritis through MAPKs, NF-κB signaling pathway

Osteoarthritis (OA) is a common joint disease characterized by degradation and inflammation of cartilage extracellular matrix. We aimed to evaluate the protective effect of Caragana sinica root (CSR) on interleukin (IL)-1β-stimulated rat chondrocytes and a monosodium iodoacetate (MIA)-induced model of OA. In vitro, cell viability of CSR-treated chondrocytes was measured by MTT assay. The mRNA expression of Matrix metallopeptidases (MMPs), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) and extracellular matrix (ECM) were analyzed by quantitative real-time PCR (qRT-PCR). Moreover, the protein expression of MAPK (phosphorylation of EKR, JNK, p38), inhibitory kappa B (IκBα) and nuclear factor-kappa B (NF-κB p65) was detected by western blot analysis. In vivo, the production of nitric oxide (NO) was detected by Griess reagent, while those of inflammatory mediators, MMPs and ECM were detected by ELISA. The degree of OA was evaluated by histopathological analyses, Osteoarthritis Research Society International (OARSI) score and micro-CT analysis. CSR significantly inhibited the expression of MMPs, ADAMTSs and the degradation of ECM in IL-1β-stimulated chondrocytes. Furthermore, CSR significantly suppressed IL-1β-stimulated of MAPKs, NF-κB signaling pathway. In vivo, CSR and Indomethacin inhibited the production of inflammatory mediators, MMPs and degradation of ECM in MIA-induced model of OA. In addition, CSR improved the severity of OA. Taken together, these results suggest CSR is a potential therapeutic active agent in the treatment of OA.