Effects of hydroxysafflor yellow A on rats with collagen-induced arthritis.

Hydroxysafflor yellow A (HSYA) from safflower (Carthamus tinctorius L.) possesses several medicinal properties. However, it is unknown whether HSYA is effective in the treatment of rheumatoid arthritis (RA). Hence, we investigated the effects of HSYA on the inflammation and synovial damage in rats with collagen-induced arthritis (CIA) by subjecting them to treatment with different doses of HSYA. Our results revealed that HSYA could significantly reduce paw swelling, pathological manifestations, and serum cytokine levels in rats with CIA. The HSYA-treated groups showed increased antioxidant enzyme activity in the serum and decreased expression of inflammatory mediators in the synovial tissues. Furthermore, HSYA treatment inhibited extracellular signal-regulated kinase (ERK) signalling pathway activation. Notably, the highest dose of HSYA (20 mg/kg) exhibited the best effects against RA symptoms. Therefore, our findings suggest that HSYA alleviates the inflammatory response and synovial damage in rats with CIA by inhibiting the ERK signalling pathway.