Effect of exercise and osteochondral injury on synovial fluid and serum concentrations of carboxy-terminal telopeptide fragments of type II collagen in racehorses.

The research investigates the effects of exercise and joint injuries on the presence of a specific type of collagen (type II) in the blood and joint fluid of thoroughbred racehorses. The findings suggest that this collagen’s presence can be used to detect cartilage damage in horses with joint injuries.

Introduction

• The study’s main objective was to determine the impact of physical exercise and osteochondral (bone and cartilage) injuries on the levels of carboxy-terminal telopeptide fragments of type II collagen (CTX-II) in synovial fluid and blood serum of Thoroughbred racehorses.
• The levels of CTX-II were compared with radiographic and arthroscopic scores, which are methods of evaluating the severity of joint injuries.

Methodology

• A total of 78 Thoroughbred racehorses, some with osteochondral injuries (38 horses) and some without (40 horses), were included in the study.
• Joint fluid and blood samples were collected both before and after a 5 to 6-month racing training from non-injured horses. From injured horses, samples were collected from the affected joint.
• These samples were analyzed using an Enzyme-Linked Immunosorbent Assay (ELISA) to determine CTX-II concentrations.
• The severity of joint injuries in the injured horses was evaluated through radiography and arthroscopy for comparison with CTX-II levels.

Results

• The study found significantly higher CTX-II levels in the joint fluid and a higher joint fluid-to-serum CTX-II ratio in injured horses as compared to pre- and post-exercise measurements in non-injured horses.
• Conversely, blood serum CTX-II concentrations were significantly lower in post-exercise and injured horse samples as compared to pre-exercise samples.
• Using the CTX-II measurements in serum and joint fluid, as well as the joint fluid-to-serum CTX-II ratio, 64% to 93% of samples were accurately categorized as pre-exercise, post-exercise, or joint-injured samples.
• Interestingly, while there was a positive correlation between arthroscopic and radiographic scores in the injured horses, these scores did not correlate with joint fluid or serum CTX-II concentration.

Conclusion

• According to the results, the concentration of CTX-II in joint fluid and blood serum, as well as the joint fluid-to-serum CTX-II ratio could serve as important indicators for detecting cartilage degradation in horses with joint injuries.