Isorhamnetin attenuates collagen-induced arthritis via modulating cytokines and oxidative stress in mice

Inflammation and oxidative stress were involved in the development and progression of rheumatoid arthritis (RA). Isorhamnetin has anti-inflammatory and anti-oxidative activities, but its effects on RA have not been investigated. In order to observe the possible therapeutic effects of isorhamnetin on RA, we established a collagen-induced arthritis mouse model and treated the animal with isorhamnetin for 3 weeks. Besides, fibroblast-like synoviocytes (FLS) were treated with lipopolysaccharide (LPS) and isorhamnetin. The severity of arthritis was assessed by arthritis score, joint destruction score and inflammation score. Levels of cytokines TNF-α, IL-1β, IL-6, IL-17A, IL-17F, IL-10 and IL-35 in the joint tissue homogenate and cell culture medium as well as anti-type II collagen antibody in serum were measured using ELISA. Contents of H2O2 and malondialdehyde (MDA) in joint tissue homogenate were measured using assay kits. We found collagen immunization induced significant arthritis in mice and isorhamnetin at the dose of 10 and 20 mg/kg/day could significantly attenuate the collagen-induced arthritis. Isorhamnetin also modulated the production of cytokines and suppressed the oxidative stress in the mice with collagen-induced arthritis at the dose of 10 and 20 mg/kg/day. These data suggested that isorhamnetin might be a potential agent for the management of RA.