HYALURONATE AND LARGE MOLECULAR-WEIGHT PROTEOGLYCANS IN SYNOVIAL-FLUID FROM HORSES WITH VARIOUS ARTHRITIDES

Objective-To investigate the presence of large molecular weight (MW) p roteoglycans (PG) and hyaluronate (HA) in synovial fluid (SF) from hor ses with various arthritides and from control joints. Design-Horses wi th acute (< 2 weeks) or chronic (> 4 weeks) lameness were examined by clinical examination, intrasynovial anesthesia, radiography, arthrosco py, and SF analysis. Joints were grouped on the basis of diagnosis: ac ute traumatic arthritis, chronic traumatic arthritis (with a subgroup of degenerative joint disease), intra-articular fracture, and infectio us arthritis, Animals-31 horses with arthritis and 9 control horses; a ltogether 43 SF samples were analyzed. Procedure-High-performance liqu id chromatography was used to assess HA and large MW PG in SF samples, Results-A PG peak was identified in 8 of 23 SF samples of joints with chronic traumatic arthritis, 4 of which had no or minimal abnormal ra diographic findings but mild articular cartilage fibrillation detected by arthroscopy, and in 3 joints with intra-articular fracture and 1 w ith resolving infectious arthritis, but not in joints with acute traum atic arthritis or in control joints. There was significant difference (P < 0.01) in mean (+/- SEM) HA concentration between control joints a nd joints with chronic traumatic arthritis (0.32 +/- 0.04 g/L; n = 9 v s 0.18 +/- 0.01 g/L; n = 23). Conclusions-Large MW PG fragments are re leased into equine SF in the course of articular disease and can be de tected simultaneously with HA by high-performance liquid chromatograph y. Clinical Relevance-The SF HA concentration can be used as diagnosti c marker for chronic traumatic arthritis. However, SF PG or other mark er cannot be used for diagnosing or monitoring degenerative joint dise ase.