Jiawei Qingluo Yin alleviates rheumatoid arthritis in rats by inhibiting activation of the Hedgehog signaling pathway to promote apoptosis of synovial cells

To investigate the mechanism of Jiawei Qingluo Yin (JWQLY) for alleviating rheumatoid arthritis (RA) in rats.

Network pharmacology, molecular docking and dynamics analyses were performed to identify the core components, key targets, and pathways of JWQLY against RA and the core component-key target binding. In a rat model of antigen-induced arthritis (AIA) established using complete Freund's adjuvant, the effects of MTX (0.5 mg/kg) and low-, medium-, and high-dose JWQLY (1.03, 3.1, and 9.3 g/kg, respectively) were tested on paw swelling, arthritis index (AI), synovial histopathology, apoptosis, and serum IL-1β and VEGF levels. In the mechanistic investigation, the rat models were treated with high-dose (9.3 g/kg) JWQLY, vismodegib (a Hedgehog inhibitor, 10 mg/kg), or both, and the changes in paw swelling, AI, histopathology, and expressions of Bcl-2, Bax, Ihh, Smo, Gli1, cleaved caspase-3, and cleaved caspase-9 were examined.

A total of 306 intersecting targets were identified between JWQLY and RA. GO and KEGG enrichment analyses revealed enrichment of the targets in negative regulation of apoptosis and inflammation and in Hedgehog and apoptosis pathways. Molecular docking studies confirmed stable binding of the core components in JWQLY to Shh and other Hedgehog targets. The rat models of AIA showed obvious paw swelling and significantly elevated AI, pathology scores, and serum IL-1β and VEGF levels, and these changes were dose-dependently alleviated by JWQLY treatment. The rat models receiving treatment with vismodegib or JWQLY+ vismodegib exhibited significantly reduced Ihh, Smo, Gli1, and Bcl-2 expression with increased expressions of Bax, cleaved-caspase-3, and cleaved-caspase-9 and apoptosis rates of the synovial cells. JWQLY and vismodegib synergistically suppressed Hedgehog signaling and enhanced synovial cell apoptosis.

JWQLY alleviates RA in rats by inhibiting Hedgehog pathway activation, down-regulating the Bcl-2/Bax ratio, and promoting synovial cell apoptosis.