Quantitation of chondroitin 4—sulfate and chondroitin 6—sulfate in pathologic joint fluid

OBJECTIVE: To investigate the correlation between joint disease and the composition of chondroitin sulfate in the joint fluid, unsaturated disaccharide isomers of chondroitin 4-sulfate (delta di-4S) and chondroitin 6-sulfate (delta di-6S) were measured in joint fluids obtained from patients with osteoarthritis (OA), rheumatoid arthritis (RA), or traumatic arthritis (TA). METHODS: These pathologic joint fluids were digested with chondroitinase ABC, and the delta di-4S and delta di-6S produced were determined by high performance liquid chromatography combined with fluorometry. RESULTS: Total content of delta di-4S plus delta di-6S was 71.8 +/- 30.0 nmoles/ml (mean +/- SD) in OA, 55.4 +/- 29.3 nmoles/ml in RA, and 211 +/- 149 nmoles/ml in TA joint fluids. The ratio of delta di-6S to delta di-4S was 3.81 +/- 0.992 in OA, 1.13 +/- 0.527 in RA, and 5.75 +/- 2.46 in TA joint fluids. Differences between groups were statistically significant. CONCLUSION: These results strongly suggest that the levels of chondroitin sulfate isomers and the delta di-6S: delta di-4S ratio in joint fluid reflect the proteoglycan metabolism of joint tissues, particularly of articular cartilage; hence, they could be used to diagnose joint diseases and to predict articular cartilage destruction from such joint diseases.