Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the synovial membranes and proliferation that leads to bone destruction and joint malformation. Biologic agents (eg, tumor necrosis factor inhibitors, interleukin [IL]-1 antagonists, NSAIDs) are clinically effective in RA patients but have toxic side effects. Nuclear factor (NF)-kB is highly activated in the pathogenesis of RA and may enhance recruitment of inflammatory cells and production of proinflammatory mediators. NF-kB also controls the expression of gene products that influence inflammation, immunity, cell proliferation, and apoptosis. Baicalin is a flavonoid found in the dry root of the medicinal plant Scutellaria baicalensis Georgi.
It is used in Asia to treat brain, hepatic, and inflammatory diseases. Evidence shows that baicalin has antiinflammatory, antioxidant, antiapoptotic, and immune regulation properties. It may have a role in anti-inflammation and immune regulation. This study investigated the effect of baicalin in a collagen-induced arthritis (CIA) model of human RA in rats.
Rats with confirmed CIA were divided into groups; each received daily intraperitoneal injections of 50, 100, or 200 mg/kg baicalin, 1 mg/kg methotrexate, or physiological saline for 30 days. Significant suppression of collagen-induced joint inflammation injury was noted in a dose-dependent manner in rats receiving baicalin. This improvement was assessed by observing decreased redness and swelling of the ankle and decreased secretion of key cytokines in pathologic synovia.