Salvianolic Acid B Suppresses Inflammatory Mediator Levels by Downregulating NF-κB in a Rat Model of Rheumatoid Arthritis

BACKGROUND Salvianolic acid B (SB) is a major active phyto-component of the plant Radix Salvia miltiorrhiza, which is traditionally used to treat joint pain and arthritis. The present study examined the anti-rheumatoid arthritis efficacy of SB on collagen-induced rheumatoid arthritis (CIA) in a rat model. MATERIAL AND METHODS Forty-eight rats were divided into 4 groups: Control rats treated with saline (Group I), rats subjected to CIA induction by intradermal injection of bovine collagen II type at the tail (Group II), and rats subjected to CIA and supplemented with either 20 or 40 mg/kg of SB for 28 days (group III or IV). RESULTS Paw swelling, edema, arthritis score, thymus and spleen indexes, and neutrophil infiltration were significantly decreased (p<0.01) by treatment with 20 or 40 mg/kg of SB. The levels of inflammatory cytokines (interleukin-1β, -6, and -17, and TNF-α) and anti-collagen II-specific immunoglobulins (IgG1 and IgG2a) were markedly decreased (p<0.01), and those of antioxidant enzymes (SOD, CAT, and GSH) were significantly increased (p<0.01) in SB-treated rats. Administration with SB (20 or 40 mg/kg) resulted in lower phosphorylated IkB-a and NF-κB p65 protein levels and markedly downregulated IκB-a expression. Furthermore, CIA rats revealed the presence of highly diffused polymorphonuclear cells (PMNs) infiltration with eroded cartilage; however, these phenomena were considerably ameliorated by SB. CONCLUSIONS SB alleviates oxidative stress and inflammation in CIA rats, thus verifying its anti-rheumatoid arthritis property.