CHANGES IN GLYCOSAMINOGLYCAN EPITOPE LEVELS IN KNEE-JOINT FLUID FOLLOWING INJURY

Objective, To measure the levels of epitopes on the chondroitin sulfat e (CS) and keratan sulfate (KS) chains of proteoglycan fragments in sy novial fluids from injured and contralateral uninjured knees of patien ts with traumatic cruciate ligament and/or meniscus damage. Methods, E nzyme-linked immunosorbent assays were used to determine the levels of monoclonal antibody epitopes 3-B-3 and 7-D-4 (CS); and 5-D-4 (KS), in paired joint fluids from the injured and uninjured knees of trauma pa tients. Results, Levels of the CS epitopes were increased in the traum a joint fluids from most patients, with higher levels of 3-B-3 epitope in 12 of the 16 patients, but the difference did not achieve signific ance; however, 7-D-4 levels were higher; in 15 patients, and the diffe rence was highly significant (P = 0.0005), In contrast, the KS epitope detected by 5-D-4 was decreased in 13 of 15 patients, and the differe nce was significant (P = 0.0074). Conclusion, The increased level of 7 -D-4 epitope on proteoglycans in joint fluid from injured knees may re flect the response of the articular cartilage to acute trauma resultin g in altered expression of specific CS epitopes on cartilage proteogly cans, The fall in KS epitope levels may reflect the synthesis of prote oglycans that have lower KS content.