... by inhibiting the synthesis of colla-gen and PG, enhancing MMP activity, reducing the synthe-sis of an IL-1 receptor antagonist by chondrocytes, and increasing susceptibility to cell injury ... [32].Cytokines produced by the synovium and chondrocytes,especially IL-1 and tumor necrosis factor alpha (TNF-α),are also key players in the degradation of cartilage [29].IL-1β is spontaneously ... IL-1β and TNF-α stimulatetheir own production and the production of othercytokines (e.g. IL-8, IL-6, and leukotriene inhibitory factor),proteases, and prostaglandin E2(PGE2) [30]. Synthesis...