Oxymatrine hydrazone (OMTH) synthesis and its protective effect for rheumatoid arthritis through downregulation of MEK/NF‐κB pathway

Rheumatoid arthritis (RA) is one of the inflammatory diseases detected in more than 1% of the world population. In the present study, oxymatrine hydrazone (OMTH) was synthesized and investigated for treatment of RA in vitro in TNF-α induced fibroblast-like synoviocyte cell model. Cell viability and apoptosis were detected using MTT and flow cytometry assays, respectively. ELISA was used for determination of inflammatory cytokines and western blotting for evaluation of protein expression. Pretreatment of HFLS-RA cells with 0.5, 1.0, 1.5, 2.0, and 2.5 μM doses of OMTH suppressed TNF-α induced promotion of proliferative potential in dose-based manner. The OMTH pretreatment of TNF-α exposed HFLS-RA cells significantly increased apoptotic cell proportion. In TNF-α exposed HFLS-RA cells OMTH pretreatment elevated Bax and suppressed Bcl-2 expression. Treatment of HFLS-RA cells with OMTH prevented TNF-α mediated elevation of IL-1β, IL-6 and IL-8. Moreover, OMTH treatment of HFLS-RA cells effectively suppressed TNF-α mediated elevated levels of MMP-1 and MMP-13. Pretreatment of HFLS-RA cells with OMTH reversed TNF-α mediated promotion of iNOS and COX-2 levels. The MEK/1/2 and p65 phosphorylation in TNF-α exposed HFLS-RA cells was reduced by OMTH pre-treatment in dose-based manner. Thus, OMTH successfully inhibited TNF-α-mediated increased viability of RA synovial cells and activated apoptosis. Pretreatment of TNF-α exposed synovial cells with OMTH targeted phosphorylation of MEK/NF-κB. Therefore, OMTH may act as potential therapeutic agent for RA treatment.