Sophocarpine suppress inflammatory response in human fibroblast-like synoviocytes and in mice with collagen-induced arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease affecting nearly 1% of adults worldwide. This study aimed to investigate whether sophocarpine is a potential drug for treating RA. The cytotoxicity of sophocarpine to RA-fibroblast-like synoviocytes (FLSs) was evaluated using 3-[4,-dimethylthiazol-2-y]-2,5-diphenyl-tetrazolium bromide (MTT) assays kit and released lactate dehydrogenase (LDH) assays. The transcription of proinflammatory cytokines in RA-FLSs was analyzed by reverse transcription and real-time polymerase chain reaction (RT-PCR). The proteins levels were further verified by enzyme-linked immunosorbent assay (ELISA). The alterations in the mediators of mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) signaling pathways were tested by western blotting. The clinical effects of sophocarpine were evaluated in type II collagen-induced arthritis (CIA) in DBA-/1 mouse model by scoring their clinical responses, synovitis, and cartilage destructions, and ELISA was employed to analyze the concentrations of proinflammatory cytokines in the serum of CIA mice. The results showed that sophocarpine contained low cytotoxicity to RA-FLS cells, and it was capable to downregulate the expressions of LPS-induced proinflammatory cytokines. The suppressions of MAPK and NF-κB signaling pathways by sophocarpine were also found in LPS-induced RA-FLSs. The attenuation of the symptoms in CIA mouse model were significant, in which concentrations of proinflammatory cytokines were decreased after the sophocarpine treatment. In this study, we demonstrated the potential of sophocarpine in treating RA, both in vitro and in vivo. Sophocarpine may be a potential drug in treating human RA.