... othercytokines (e.g. IL-8, IL-6, and leukotriene inhibitory factor),proteases, and prostaglandin E2(PGE2) [30]. Synthesis of the inflammatory cytokines IL-1 and TNF-α and expression of their ... degradation exceeds synthesis. The balance between synthesis and degradation is affected byage and is regulated by several factors produced by the synovium and chondrocytes, including cytokines, growthfactors, ... in OA [29,31]. The activity of many MMPs increases in OA by either an increase in theirown synthesis, an increased activation by their proen-zymes, or decreased activity of their inhibitors...