Evaluation of glycosaminoglycans levels in normal joint fluid of the knee.

Glycosaminoglycans (GAGs) level in joint fluid have been investigated in various joint diseases as a joint maker. However, there are very few studies of normal joint fluid providing a baseline for a better understanding of altered GAGs level in pathological joint fluid. We investigated GAGs level in knee joint fluid for 25 healthy young volunteers with a mean age of 27.5 years (range: 18 to 36 years). Biochemical evaluations included the concentration of hyaluronic acid (HA), chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate (C6S), and the C6S/C4S ratio. The unsaturated disaccharides derived from HA by Morgan-Elson methods, and those from CS were measured with high performance liquid chromatography. The mean HA concentration was 3.4+/-0.6 mg/ml. The mean concentration of C4S and C6S, and C6S/C4S ratio were 19.0+/-4.9 nmol/ml, 125.5+/-44.4 nmol/ml and 6.5+/-1.1 respectively.