Bufalin, a bioactive component of the Chinese medicine chansu, inhibits inflammation and invasion of human rheumatoid arthritis fibroblast-like synoviocytes.

Rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) contribute to the destruction of cartilage and bone by production of metalloproteinases (MMPs) into the synovial fluid and by direct invasion into extracellular matrix (ECM). Bufalin, a major component of Venenum Bufonis, can attenuate the invasion of various cancer cells. Here, we investigated the effects of bufalin on tumor necrosis factor-alpha (TNF-α)-induced invasion of RAFLSs. Western blot analysis and electrophoretic mobility shift assay were conducted to analyze the nuclear translocation of p65/nuclear factor-kappa B (NF-κB) and NF-κB DNA-binding activity. Semiquantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed to assess the expression of cytokines. Our results revealed that TNF-α significantly increased p65 translocation into nucleus (P < 0.01) and enhanced NF-κB DNA-binding activity, which were dose-dependently inhibited by bufalin. Furthermore, bufalin attenuated the TNF-α-induced interleukin-1beta (IL-1β), IL-6, and IL-8 production in RAFLSs in a concentration-dependent manner. Interestingly, TNF-α-induced invasion of RAFLSs was dampened by the pretreatment of bufalin. Additionally, bufalin decreased the mRNA abundance and secretion of MMP-9 in TNF-α-treated RAFLSs. Our results reveal that bufalin can inhibit TNF-α-induced NF-κB activation, cytokine production, invasion, and MMP-9 expression in RAFLSs, indicating a therapeutic potential of bufalin on RA.