Cytokines in cartilage injury and repair

Joint injury results in cartilage lesions that are characterized by a poor repair response, and such lesions often progress to osteoarthritis. Acute j oint injury or chronic exposure of cartilage to an abnormal biochemical or biomechanical environment results in the activation of chondrocytes. This c hondrocyte response is manifested by enhanced cell proliferation and death, matrix degradation, and new matrix synthesis. Cytokines are important stim uli of this chondrocyte activation response and trigger joint inflammation that can accompany cartilage injury. The presence of cytokines in cartilage is associated with abnormal extracellular matrix remodeling and loss, ther efore defining them as a class of targets for therapeutic interventions. In sight into intracellular signaling mechanisms that are activated by cytokin es; may provide the basis for pharmacologic interventions that promote cart ilage repair.