Therapeutic effects of astragalus polysaccharides on inflammation and synovial apoptosis in rats with adjuvant-induced arthritis

Background: Rheumatoid arthritis (RA), an autoimmune disease, is characterized by pronounced inflammation and cell accumulation within affected joints. Beneficial effects of active ingredients of the astragalus root (Radix astrogali) in treatment of immunological diseases have been previously observed, but the mechanisms are not well understood. This study aims to evaluate therapeutic effects and the mechanisms of astragalus polysaccharides (APS) on adjuvant-induced arthritis (AA) in rats. Methods: Effects of treatment of AA rats with increasing doses of APS, Tripterygium glycosides (positive control) and saline (negative control) on swelling, arthritic index, synovial cell accumulation, serum concentrations of tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta), synovial apoptosis and immunostaining for Bcl-2 and Bax were determined. Results: APS treatment reduced cell accumulation, swelling and arthritic index of the joints and serum concentrations of TNF-alpha and IL1-beta in a dose-dependent manner in AA rats. Synovial cell apoptosis was elevated in response to APS treatment and accompanied by increased staining for pro-apoptotic Bax protein and decreased staining for anti-apoptotic Bcl-2 protein. Conclusions: APS treatment reduced multiple indices of arthritis in rats with AA. Results support further investigation of therapeutic effects of APS in treatment of RA and other autoimmune diseases.