Abstract
OBJECTIVES: To explore the therapeutic mechanism of puerarin for alleviating synovitis in rats with collagen-induced arthritis (CIA). METHODS: In a SD rat model of CIA, we tested the effects of daily gavage of puerarin at low, moderate and high doses (10, 30, and 100 mg/kg, respectively) for 3 weeks, with tripterygium glycosides (GTW, 10 mg/kg) as the positive control, on swelling in the hind limb joints regions evaluated by arthritis index scoring. Mass fraction of the liver of the rats was calculated, and pathologies in joint synovial membrane were observed with HE staining. The expressions of transforming growth factor β‑activated kinase-1 (TAK1), Toll-like receptor 4 (TLR4), and nuclear factor kappa-Bp65 (NF‑κB p65) at the mRNA and protein levels in the synovial tissues were detected using Real-time PCR and Western blotting. RESULTS: Compared with those in the model group, the rats in GTW group and high-dose puerarin group showed significantly reduced mass fraction of the liver. Treatment with GTW and puerarin at the 3 doses all significantly alleviated plantar swelling, lowered arthritis index scores, and improved synovitis in CIA rats (P<0.05), and the effects of puerarin showed an obvious dose dependence. Both GTW and puerarin treatments significantly lowered TAK1, TLR4, and NF‑κB p65 mRNA and protein expressions in the synovium of CIA rats. CONCLUSIONS: Puerarin alleviates synovium damages in CIA rats possibly by suppressing the TLR4/NF‑κB signaling pathway via downregulating TAK1 expression.