The biochemical differences of the superficial digital flexor tendon and the common digital extensor tendon between Warmbloods, Friesians and Thoroughbreds.

Abstract

Summary Reasons for performing this study: Research has shown that the suspensory ligament (tendo interosseus), the superficial and deep digital flexor tendon of Friesians biomechanically differ from the same tendons in ponies. The tendons of Friesians are more elastic compared to those of ponies. It is not clear yet which biochemical components are responsible for this fact. For thoroughbreds, a study showed that the pyrrole and pyridinoline cross-links have an effect on the stiffness and strength of their tendons. There is, as far as known, no research done whether these crosslinks could cause the differences in biomechanical properties of the tendons of Friesians and Warmbloods. Hypothesis: The crosslinks pyrrole and pyridinoline cause the biomechanically differences in elasticity between the tendons of Friesians and Warmbloods. Methods: The superficial digital flexor tendon (SDFT) and common digital extensor tendon (CDET) were collected from 12 Warmbloods, 12 Friesians and 8 Thoroughbreds. They were biomechanically tested for water content, crosslink levels (pyrrole and pyridinoline), cellularity, glycosaminoglycans (GAGs) and collagen. Results: Friesian tendon contain a significant higher pyrrole crosslink level than Thoroughbred tendon. No significant difference is found for the pyridinolines. Conclusions: The higher content of pyrrole in Friesian tendon could be one of the causes of the biomechanically differences in elasticity, but further research is necessary.