Changes in synovial fluid and serum biomarkers with exercise and early osteoarthritis in horses.

This research examines the differences in biomarker changes in horses due to exercise as compared to those with early onset osteoarthritis (OA). The study used 16 horses enforced with a heavy exercise regimen and manipulated OA in a select group to evaluate biomarker changes in synovial fluid and serum.

Methods and Procedures

This study began with a set of 16 two-year-old horses which were categorized into two groups – just undergoing exercise and another group with induced OA performing exercise. The OA group had OA stimulated in one mid-carpal joint. Post two weeks from the surgical operation, all the horses initiated a mounting exercise program.

The researchers conducted a weekly evaluation of the following aspects:

• Clinical outcomes
• Synovial fluid biomarkers
• Serum biomarkers

The synovial and serum biomarkers tested included epitope CS846 (CS846), epitope CPII (CPII), glycosaminoglycans (GAGs), epitope Col CEQ (Col CEQ), type I and II collagen degradation fragments (C1,2C), osteocalcin, C-terminal of bone type I collagen (CTX1), type I collagen (Col I), and (synovial fluid only) prostaglandin E2 (PGE2) levels.

At the end of the 91-day period, all horses were euthanized, and their joints were evaluated using gross, histopathological, and histochemical assessments.

Results and Findings

The outcomes of the experiment showed that exercise influenced a significant escalation in the concentration of several synovial fluid biomarkers, including CS846, CPII, GAG, Col CEQ, C1,2C, osteocalcin, and Col I.

A similar increase in these biomarkers was also noted in the synovial fluid collected from the joints of OA-affected horses, with the addition of PGE2 as compared to joints from horses that underwent exercise alone.

Serum levels of CS846, CPII, GAG, osteocalcin, C1,2C, and Col I also showed a significant increase with exercise. A further increase in the concentration of these serum biomarkers was recorded in OA-affected horses compared to those undergoing exercise alone.

Conclusion

The findings of this study show that six specific synovial fluid and serum biomarkers played a crucial role in distinguishing between horses affected by early OA and those subjected to exercise alone. However, three biomarkers – synovial fluid CTX1 and serum Col CEQ and CTX1 – did not prove fruitful for this discrimination.