anti‐RA effect of STBT and to evaluate the potential mechanisms underlying collagen-induced arthritis (CIA) in rats. CIA model Wistar rats were induced with bovine type II collagen. The rats were immunized with CIA and were treated with STBT

Shuangtengbitong tincture (STBT), a clinical prescription from the Fujian University of Traditional Chinese Medicine (TCM) Affiliated People's Hospital (Fuzhou, China), has been used in the treatment of rheumatoid arthritis (RA) for ~10 years. The aim of the current study was to confirm the anti‐RA effect of STBT and to evaluate the potential mechanisms underlying collagen-induced arthritis (CIA) in rats. CIA model Wistar rats were induced with bovine type II collagen. The rats were immunized with CIA and were treated with STBT (0.5 and 2 ml/injection) and votalin (~1 cm/injection) continuously for ~1 month. Following treatment, the pathological sections of CIA rat joints were observed by hematoxylin and eosin staining, expression of toll-like receptor-4 (TLR4), myeloid differentiation factor 88 (MyD88) and nuclear transcription factor-κB (NF-κB) were investigated by western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Following treatment, STBT significantly suppressed paw swelling (P<0.05) compared with the model group and increased body weight. STBT also reversed pathological changes, STBT‐treated rats showed a significant improvement of synovial hyperplasia, inflammatory infiltration, and cartilage and bone destruction. The levels of protein and mRNA expression of TLR4, MyD88 and NF-κB were markedly suppressed in the synovial tissue of STBTand votalin-treated rats. In addition, STBT showed marked inhibition of the levels of protein and mRNA expression of TLR4, MyD88 and NF-κB at an STBT volume ranging between 1 and 4 ml/day, indicating that the inhibition was volume dependent. These results show that STBT inhibits CIA and may be correlated with TLR4, MyD88 and NF-κB expression.