STROMELYSIN, TISSUE INHIBITOR OF METALLOPROTEINASES AND PROTEOGLYCAN FRAGMENTS IN HUMAN KNEE-JOINT FLUID AFTER INJURY

Objective. To determine in a cross sectional study the concentrations of stromelysin, tissue inhibitor of metalloproteinases (TIMP), and pro teoglycan fragments in knee synovial fluid (SF) at different times aft er injury to cruciate ligament or meniscus. Methods. Joint fluid sampl es were obtained from patients with knee injury diagnosed by arthrosco py. Concentrations of stromelysin-1 and TIMP-1 were determined by immu noassay with monoclonal and polyclonal antibodies. Cartilage proteogly can fragments were quantified by immunoassay with polyclonal antibodie s or by dye precipitation. Results. Average concentrations of stromely sin increased 40-fold in association with injury, and after about 6 mo nths decreased to a plateau level about 10-fold increased compared to a reference group with healthy knees. TIMP and proteoglycan levels als o increased in similar temporal patterns, but less markedly. Increased average SF levels of these markers were maintained for at least 17 ye ars after injury. SF from knees with injury contained a 1.5 to 2.5 mol ar excess of stromelysin over TIMP, while reference joint fluids conta ined a 2-fold molar excess of TIMP over stromelysin. Conclusion. The p ersistent changes in SF markers after joint injury may be associated w ith the cartilage destruction and frequent development of posttraumati c osteoarthritis in this group of patients.