Measurement of cartilage oligomeric matrix protein (COMP) in normal and diseased equine synovial fluids.
OBJECTIVE
This study was designed to assay cartilage oligomeric matrix protein (COMP) in equine synovial fluids and to compare the concentration in synovial fluids from normal horses with joint diseased horses. The relationship between the COMP degradation and the matrix metalloproteinase activity in synovial fluids was also investigated.


METHODS
Using COMP antigen prepared from equine articular cartilage and murine monoclonal antibody (12C4) raised against human COMP, an inhibition ELISA was developed. COMP in equine synovial fluids from normal and diseased joints was quantified. Metalloproteinase activities were evaluated in the same synovial fluids by a gelatin degradation ELISA. COMP fragments were evaluated qualitatively by Western blotting.


RESULTS
The COMP inhibition ELISA was reliable at concentrations of equine COMP between 62.5 and 2000 ng/ml. COMP values in joint fluids in both aseptic and septic joint disease (19.7+/-15.3 and 16.1+/-11.2 microg/ml, respectively) were significantly (P < 0.001) lower than normal (53.2+/-29.0 microg/ml). The molecular sizes of COMP on immunoblots were different between normal and diseased synovial fluids; more fragments were seen in diseased fluids. The aseptic (26.6 +/- 20.6%) and septic joint disease synovial fluids (36.1 +/- 37.5%) had significantly higher (P < 0.02 and 0.002, respectively) gelatinolytic activities than normal (13.6 +/- 13.7%). There was a negative correlation (R = -0.31, P < 0.002) between COMP level and gelatinase activity. Conclusions We conclude that the fragment pattern and the absolute COMP concentration maybe useful for monitoring joint disease, and that COMP degradation in synovial fluids from progressed joint disease may be due to MMP gelatinolytic activity.
Department of Veterinary Surgery, Kagoshima University, 21-24 Korimoto 1-chome, Kagoshima, 890-0065, Japan.
K
K
Misumi
V
V
Vilim
P D
PD
Clegg
C C
CC
Thompson
S D
SD
Carter
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D064236:Cartilage Oligomeric Matrix Protein; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005780:Gelatin / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D006614:Hindlimb; D006734:Horse Diseases / Q000175:diagnosis*; D006736:Horses; D007592:Joint Diseases / Q000175:diagnosis* / Q000662:veterinary; D007596:Joints / Q000378:metabolism*; D064235:Matrilin Proteins; D013582:Synovial Fluid / Q000737:chemistry*
D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; C577553:TSP5 protein, human; D005780:Gelatin