In vivoand in vitroanti-arthritic efficacy of a herbal formula consisting of Rosae Multiflorae Fructus and Lonicerae Japonicae Flos

OBJECTIVE Rheumatoid arthritis(RA)is the most common inflammatory autoimmune disease,affecting around 1% of the world population.Toll-like receptor 4(TLR4)signalling has been found to be involved in the pathogenesis of RA.It is a potential therapeutic target for RA treatment.A herbal formula(RL)consisting of Rosae Multiflorae Fructus and Lonicerae Japonicae Flos has traditionally been used in treating various inflammatory disorders.In this study,we would evaluate the anti-arthritic effect of RL on collagen-induced arthritis(CIA)in rats and investigate the involvement of TLR4 signaling in the mode of action of RL in vivo and in vitro.METHODS In vivo anti-arthritic efficacy was evaluated using CIA rats induced by bovine typeⅡ collagen.The treatment groups were treated with various concentrations of RL or positive control indomethacin for 35 d.Clinical signs(hind paw volume and arthritis severity scores),changes in serum inflammatory mediators,histological and radiographic changes of joints were investigated.Spleens and peritoneal macrophages were used to determine the effects of RL on innate and adaptive immune responses in CIA rats.The involvement of TLR4 signalling pathways in the anti-arthritic effect of RL was examined in cartilage tissue of CIA rats,murine RAW264.7macrophages and human THP-1 monocytic cells.RESULTS The severity of arthritis in the CIA rats was significantly attenuated by RL.Histological score and radiographic score were efficiently improved by RL.RL could also dose-dependently inhibit pro-inflammatory cytokines in serum of CIA rats.RL significantly inhibited the production of various pro-inflammatory mediators,the expression and/or activity of the components of TLR4 signalling pathways in animal tissue and cell lines.CONCLUSION RL possesses anti-arthritic effect on collagen-induced arthritis in rats.The therapeutic effect of RL may be related to its inhibition on pro-inflammatory cytokines in serum.The inhibition of the TLR4/TAK1/NF-κB and TLR4/TAK1/MAPK pathways participate in the anti-arthritic effects of RL.This provides a pharmacological justification for the use of RL in the control of various arthritic diseases.Further investigation should be done to develop RL into a modern anti-arthritic agent.