RESUMO
OBJECTIVE Aryl hydrocarbon receptor (Ahr) is thought to be a crucial factor that regulates immune responses, which may be involved in the pathogenesis of autoimmune inflammation including rheumatoid arthritis (RA). The results of our group in recent years have shown that CP-25, a novel ester derivative of paeoniflorin, has a good effect on improving RA animal models. However, whether the anti-arthritis effect of CP-25 is related to Ahr remains unclear. METHODS CP-25 treatment ameliorated adjuvant-induced arthritis (AA), a mouse model of RA, by inhibiting Ahr-related activities in fibroblasts like synoviocytes (FLS). AA rats were treated with CP-25 or paroxetine from day 17 to 33 after immunization. RESULTS CP-25 alleviated arthritis symptoms and the pathological changes, decreased the expression of Ahr in the synovium and FLS of AA rats. Besides, treatment with CP-25 reduced the proliferation and migration of MH7A caused by Ahr activation. In addition, we also demonstrated that CP-25 down-regulated the co-expres?sion and co-localization of Ahr and G protein-coupled receptor kinase 2 (GRK2) in MH7A. CONCLUSION The data pre?sented here demonstrated that CP-25 suppressed FLS dysfunction in rats with AA, which were associated with reduced Ahr activation and the interaction between Ahr and GRK2.