Cynanchum komarovii extract for the treatment of rheumatoid arthritis by acting on synovial cells in vitro and in vivo

Ethnopharmacological relevance: Cynanchum komarovii (CK), the northwest Chinese region's common medicinal herb, was traditionally utilized to treat arthritis, toothache, bald sores and cholecystitis. Various forms of arthritis can be treated with CK, based on "Medicinal Plants of Chinese Desert Areas". However, the exact mechanism of action in rheumatoid arthritis (RA) is uncertain.Aim of the study: To evaluate the in vitro and in vivo effects of CK extracts on RA and to preliminarily investigate its anti-RA mechanism of action.Materials and methods: The main components of CK extract were analyzed by HPLC method. The effects of CK on the proliferation and apoptosis of human rheumatoid arthritis fibroblast-like synoviocytes (HFLS-RA) cells and the expression of apoptosis-related proteins in HFLS-RA cells were evaluated by CCK8 assay, flow cytometry and WB assay. To verify the anti-RA effect of CK extracts in vivo, a collagen-induced arthritis (CIA) rat model was established. The rats were divided into six groups: normal group, model group, CK high-dose group (1000 mg/kg, CK-H), CK medium-dose group (500 mg/kg, CK-M), CK low-dose group (250 mg/kg, CK-L) and methotrexatepositive drug group (MTX); the drug was administered continuously for 28 days. Body weight changes, joint swelling, arthritis index, bone density, ankle lesions, immune organ index, splenic lesions and inflammatory factor expression were used to evaluate the in vivo anti-RA activity of the extract.Results: The findings of in vitro experiments showed that 10% CK-containing serum decreased the expression level of Bcl-2, increased the expression levels of Bax and Cleaved Caspase-3 in synovial cells, and prevented TNF-& alpha; induced aberrant proliferation and apoptotic antagonism in HFLS-RA cells. According to in vivo studies, CK extract at doses above 250 mg/kg was effective in controlling the levels of inflammatory factors, lowering the arthritis index, and improving foot swelling in CIA rats. When administered at doses up to 1000 mg/kg, CK extract significantly improved synovial lesions, increased bone density, and decreased abnormally elevated immune organ index in CIA rats.Conclusions: CK has significant anti-RA activity, and its anti-RA mechanism of action may be related to the regulation of the expression levels of apoptosis related proteins and the promotion of apoptosis in synovial cells.