Extracellular matrix composition of the equine superficial digital flexor tendon: relationship with age and anatomical site.

The research focuses on the composition of an equine tendon, specifically the Superficial Digital Flexor Tendon (SDFT), and how it changes with age and anatomical location. The study finds that once adulthood is achieved, the tendon composition displays minimal alterations with age, but differs significantly between different anatomical areas, due to varied biomechanical loading.

Research Objectives and Hypotheses

• The research aimed to test two primary hypotheses. The first hypothesis was that the equine SDFT, just like the articular cartilage, have distinct biochemical compositions in areas with different biomechanical loads. The second hypothesis stated that the biochemical composition of the SDFT would not experience significant changes with age, once adulthood is reached, similar to the articular cartilage.

Research Methodology

• The researchers obtained tendon samples from 60 mature horses that were destined for slaughter. The samples were collected from two specific areas of the SDFT – a central area in the mid-metacarpal region and at the point of the proximal sesamoid bones (sesamoid region).
• They then analyzed these samples to determine their collagenous and non-collagenous components.

Research Findings and Conclusion

• The study found no correlation between age and the biochemical composition in either region of the tendon, except for one parameter. A significant increase in pentosidine cross-links was observed with age in the sesamoid region.
• Significant differences were also found in all the other variables between the two anatomical regions under study, except for the hydroxylysylpyridinoline cross-links. suggesting that the tendon’s composition varies between anatomical regions due to different modes of biomechanical loading.
• The researchers concluded that, akin to articular cartilage, most molecular parameters of the equine SDFT are not influenced by age in mature horses, indicating a low rate of remodeling. This supports the second hypothesis. The first hypothesis was also supported, as clear differences were found in the tendon composition between the two anatomical regions.