Effect of exercise and osteochondral injury on synovial fluid and serum concentrations of carboxy-terminal telopeptide fragments of type II collagen in racehorses.
OBJECTIVE
To investigate the effects of exercise and osteochondral injury on concentrations of carboxy-terminal telopeptide fragments of type II collagen (CTX-II) in synovial fluid (SF) and serum of Thoroughbred racehorses and to compare findings with radiographic and arthroscopic scores of joint injury severity.


METHODS
78 Thoroughbreds with (n = 38) and without (40) osteochondral injury.


METHODS
Serum and metacarpophalangeal or carpal joint SF samples were collected from noninjured horses before and at the end of 5 to 6 months of race training (pre- and postexercise samples, respectively) and from horses with osteochondral injury (1 joint assessed/horse). Synovial fluid and serum CTX-II concentrations were determined by use of an ELISA. Radiographic and arthroscopic scores of joint injury severity were determined for the injured horses.


RESULTS
The CTX-II concentrations in SF and SF:serum CTX-II ratio were significantly higher for horses with joint injuries, compared with pre- and postexercise findings in noninjured horses. Serum CTX-II concentrations in postexercise and injured-horse samples were significantly lower than values in pre-exercise samples. On the basis of serum and SF CTX-II concentrations and SF:serum CTX-II ratio, 64% to 93% of serum and SF samples were correctly classified into their appropriate group (pre-exercise, postexercise, or injured-joint samples). In horses with joint injuries, arthroscopic scores were positively correlated with radiographic scores, but neither score correlated with SF or serum CTX-II concentration.


CONCLUSIONS
Results suggested that serum and SF CTX-II concentrations and SF:serum CTX-II ratio may be used to detect cartilage degradation in horses with joint injury.
Cleary
Orlaith B
OB
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Trumble
Troy N
TN
Merritt
Kelly A
KA
Brown
Murray P
MP
D000818:Animals; D001182:Arthroscopy / Q000662:veterinary; D015415:Biomarkers / Q000032:analysis; D002358:Cartilage, Articular / Q000293:injuries*; D024043:Collagen Type II / Q000378:metabolism*; D006734:Horse Diseases / Q000378:metabolism*; D006736:Horses / Q000293:injuries*; D007592:Joint Diseases / Q000378:metabolism / Q000662:veterinary; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012420:Running; D013582:Synovial Fluid / Q000737:chemistry
D015415:Biomarkers; D024043:Collagen Type II