Introduction:Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by inflammation of the synovial tissues that leads to the articular cartilage breakdown,causing severe morbidity and disability (Hochberg M,2008).Cartilage breakdown has still been a great clinical challenge for rheumatologists during RA treatment (Yuan F,2012).It is desirable to understand the molecular mechanisms to develop therapeutic strategies toward blockade of cartilage breakdown in RA.