Hyaluronate and large molecular weight proteoglycans in synovial fluid from horses with various arthritides.

OBJECTIVE

To investigate the presence of large molecular weight (MW) proteoglycans (PG) and hyaluronate (HA) in synovial fluid (SF) from horses with various arthritides and from control joints.

DESIGN

Horses with acute (< 2 weeks) or chronic (> 4 weeks) lameness were examined by clinical examination, intrasynovial anesthesia, radiography, arthroscopy, and SF analysis. Joints were grouped on the basis of diagnosis: acute traumatic arthritis, chronic traumatic arthritis (with a subgroup of degenerative joint disease), intra-articular fracture, and infectious arthritis.

ANIMALS

31 horses with arthritis and 9 control horses; altogether 43 SF samples were analyzed.

PROCEDURE

High-performance liquid 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 radiographic findings but mild articular cartilage fibrillation detected by arthroscopy, and in 3 joints with intra-articular fracture and 1 with resolving infectious arthritis, but not in joints with acute traumatic arthritis or in control joints. There was significant difference (P < 0.01) in mean (+/- SEM) HA concentration between control joints and joints with chronic traumatic arthritis (0.32 +/- 0.04 g/L; n = 9 vs 0.18 +/- 0.01 g/L; n = 23).

CONCLUSION

Large MW PG fragments are released into equine SF in the course of articular disease and can be detected simultaneously with HA by high-performance liquid chromatography.

CLINICAL RELEVANCE

The SF HA concentration can be used as diagnostic marker for chronic traumatic arthritis. However, SF PG or other marker cannot be used for diagnosing or monitoring degenerative joint disease.