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Equine veterinary journal1999; 31(5); 391-396; doi: 10.1111/j.2042-3306.1999.tb03838.x

Age-related changes to the molecular and cellular components of equine flexor tendons.

Abstract: Specific tendons show a high incidence of partial central core rupture which is preceded by degeneration. In the performance horse, the superficial digital flexor tendon (SDFT) is most often affected. We have described previously the molecular changes that are associated with degeneration in the central core region of the equine SDFT. The pathophysiological mechanism leading to change in synthetic activity of central zone cells in degenerated tendons is not known. In this study, we test the hypothesis that ageing results in matrix composition changes within the central zone of the SDFT. Extracellular matrix composition and cellularity were analysed in equine SDFTs collected from Thoroughbred horses and compared with a flexor tendon which rarely shows degenerative change and subsequent injury (deep digital flexor tendon, DDFT). Data were examined for age-related changes to central and peripheral zone tissue of the SDFT and DDFT. Ageing in both tendons (SDFT and DDFT) resulted in a significant increase in collagen-linked fluorescence and a decrease in cellularity in the DDFT but not the SDFT. The central zone tissue from the SDFT had a significantly higher proportion of type III collagen than the peripheral zone of the tendon. The highest level of type III collagen was found in the central zone tissue of the SDFT from the older group of horses and this may represent the early stages of a degenerative change. Collagen content did not differ between the 2 flexor tendons; however, there were differences in collagen type and organisation. The SDFT had a higher type III collagen content, higher levels of the mature trifunctional collagen crosslink hydroxylysylpyridinoline, lower total chondroitin sulphate equivalent glycosaminoglycan content, smaller diameter collagen fibrils and a higher cellularity than the DDFT. In conclusion, differences in macromolecular composition exist between the flexor tendons and ageing contributes to a tendon specific change in composition.
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Publication Date: 1999-10-03 PubMed ID: 10505954DOI: 10.1111/j.2042-3306.1999.tb03838.xGoogle Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study investigates age-related changes in the composition of horse tendons, specifically the superficial and deep digital flexor tendons, and how these changes might contribute to tendon damage and rupture. The findings highlight significant differences in the tissue makeup of these two tendon types, as well as changes that occur with age, potentially pointing to the early stages of tendon degeneration.

Objective and Methodology

The research was designed to test the theory that aging results in changes to the matrix composition in the central zone of horse tendons, particularly the superficial digital flexor tendon (SDFT) commonly affected by degeneration and rupture in performance horses. In comparison, researchers used the deep digital flexor tendon (DDFT), a tendon that rarely shows degenerative change. Both were sourced from Thoroughbred horses.

  • Both the SDFT and DDFT were assessed for age-related changes in their central and peripheral zone tissues.
  • The researchers primarily focused on the composition of the extracellular matrix (the non-cell components of tissues) and cellularity (the density of cells).

Key Findings

The study found various significant age-related changes in both tendons, including an increase in collagen-linked fluorescence – a marker of collagen aging. There was also a decrease in cellularity in the DDFT, though not in the SDFT.

  • The central tissue of the SDFT had a notably higher percentage of type III collagen than the peripheral zone of the same tendon. This type of collagen is usually associated with tissue repair and remodeling, which often increases with injury or disease.
  • Older horses had the highest levels of type III collagen in the SDFT, suggesting the beginnings of degenerative change.
  • While overall collagen content didn’t differ between the two tendons, there were differences in collagen type and arrangement. The SDFT had a higher type III collagen content, greater levels of a mature trifunctional collagen crosslink (hydroxylysylpyridinoline), and smaller diameter collagen fibrils.
  • The SDFT also had higher cellularity (cell density) than the DDFT.

Conclusion

The results of the study underscore significant differences in the macromolecular composition between the flexor tendons examined. Moreover, aging seems to contribute to tendon-specific changes in composition, with the SDFT showing strong signs of potential early-stage degenerative change. These changes could be potential precursors or indictors of tendon damage or rupture in equines, thus leading to better prevention and treatment strategies.

Cite This Article

APA
Birch HL, Bailey JV, Bailey AJ, Goodship AE. (1999). Age-related changes to the molecular and cellular components of equine flexor tendons. Equine Vet J, 31(5), 391-396. https://doi.org/10.1111/j.2042-3306.1999.tb03838.x

Publication

Equine veterinary journal
ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 31
Issue: 5
Pages: 391-396

Researcher Affiliations

Birch, H L
  • Veterinary Basic Sciences, Royal Veterinary College, North Mymms, Hatfield, UK.
Bailey, J V
    Bailey, A J
      Goodship, A E

        MeSH Terms

        • Aging / pathology
        • Amino Acids / analysis
        • Animals
        • Collagen / analysis
        • Collagen / classification
        • DNA / analysis
        • Extracellular Matrix / chemistry
        • Extracellular Matrix / pathology
        • Glycosaminoglycans / analysis
        • Horses / injuries
        • Microscopy, Electron / veterinary
        • Myofibrils / pathology
        • Myofibrils / ultrastructure
        • Rupture / etiology
        • Rupture / veterinary
        • Tendon Injuries / etiology
        • Tendon Injuries / veterinary
        • Tendons / pathology
        • Tendons / ultrastructure
        • Water / analysis

        Citations

        This article has been cited 30 times.
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