TNF and rheumatoid arthritis: It is well-documented that pro-inflammatory cytokines such as IL-1β, TNF-α, and TNF-ß stimulate matrix-degrading enzymes such as MMPs and COX-2 by promoting NF-κB, which leads to the destruction of the cartilage matrix and joint inflammation and which plays an important role in the pathogenesis of RA and OA [37].