TNF and osteoarthritis: Mechanistically, these anti-osteoarthritis effects were associated with upregulated expression of COL2A1 and aggrecan in the articular cartilage, along with a decrease in inflammatory mediators (NO, PGE2), cytokines (IL-6, IL-1, TNFα), and cartilage-degrading enzymes (MMP-3 and MMP-13) in serum.