Quantitative microanalysis of equine synovial fluid glycosaminoglycan concentration

An alcian blue precipitation method for quantifying the hyaluronic acid (HA) and sulphated glycosaminoglycan concentration (SGAG) in solutions containing both compounds was assessed. The assay was found to be rapid and reliable in solutions containing 0 to 200 mg of HA/dl and 50 to 1,000 micrograms of SGAG/dl, and was not affected by the presence of protein, hemoglobin, or methemoglobin in concentrations normally found in synovial fluid. The HA and SGAG concentrations in intercarpal synovial fluid from 13 clinically normal and 11 arthritic horses were evaluated. A relationship was not found between the concentration of HA and SGAG and any other synovial fluid variable. The SGAG concentration was found to be markedly high in several of the synovial fluid samples from arthritic horses, but did not correlate with the degree of articular cartilage erosion.