Mechanical properties of the equine superficial digital flexor tendon relate to specific collagen cross-link levels.
Abstract: Damage to the flexor tendons, particularly the superficial digital flexor tendon (SDFT), is one of the most common musculoskeletal injuries sustained by horses competing in all disciplines. Our previous work has shown that SDFTs from different individuals show a wide variation in mechanical strengths; this is important clinically as it may relate to predisposition to injury. The high mechanical strength of tendon relies on the correct orientation of collagen molecules within fibrils and stabilisation by the formation of chemical cross-links between collagen molecules. It is not known whether the variation in SDFT mechanical properties between individuals relates to differences in collagen cross-link levels. Objective: Enzyme-derived, intermolecular cross-linking of tendon collagen correlates with mechanical properties of the SDFT. Methods: SDFTs were collected from 38 horses and mechanically tested to failure. Structural and material properties were calculated from the load/deformation plot and cross-sectional area for each tendon. Following mechanical testing, pyrrolic cross-link levels were measured using a spectrophotometric assay for Ehrlich's reactivity and pyridinoline levels were quantified by HPLC. Cross-link levels were correlated with mechanical properties and statistical significance tested using a Pearson's correlation test. Results: Pyrrole cross-link levels showed a significant positive correlation with ultimate stress (P = 0.004), yield stress (P = 0.003) and elastic modulus (P = 0.018) of the tendons, despite being a minor cross-link in these tendons. There was no significant correlation of mechanical properties with either hydroxylysyl- or lysyl-pyridinoline levels. Conclusions: Given the low absolute levels of pyrrole, we suggest that the correlation with high mechanical strength is through an indirect mechanism. Understanding the nature of the relationships between pyrrole cross-links, other matrix characteristics and tendon material properties may allow development of strategies to identify horses at risk from tendon injury and be of value in informing training practices.
© 2010 EVJ Ltd.
Publication Date: 2011-05-27 PubMed ID: 21059057DOI: 10.1111/j.2042-3306.2010.00175.xGoogle Scholar: Lookup
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Summary
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This research investigates the mechanical properties of a specific horse tendon, the superficial digital flexor tendon (SDFT), and their relation to levels of collagen cross-linking. It suggests that varying levels of a minor cross-link called “Pyrrole” may influence the tendon’s strength, thus potentially predicting injury risk in horses.
Objective and Importance
- The primary aim of this research is to understand the correlation between the enzyme-derived, intermolecular cross-linking of tendon collagen and the mechanical properties of the SDFT in horses.
- Damage to flexor tendons, such as the SDFT, is a frequently occurring issue in horses involved in multiple disciplines, leading to musculoskeletal injuries.
- A thorough understanding of this relationship can help inform training practices, possibly serving to preemptively identify horses at risk for tendon injury.
Methods Used
- SDFT tendons were acquired from 38 horses and subsequently mechanically evaluated to the point of failure.
- Each tendon’s structural and material properties were determined from finding the area under the load/deformation plot and their individual cross-sectional areas.
- After the mechanical testing phase, pyrrolic and pyridinoline cross-link levels were measured using a spectrophotometric assay for Ehrlich’s reactivity and high-performance liquid chromatography (HPLC) respectively.
- Finally, a Pearson’s correlation test was used to study the relationship between cross-link levels and mechanical properties.
Key Findings
- Results show a substantial positive correlation between Pyrrole cross-link levels and the ultimate stress, yield stress, and elastic modulus aspects of the tendons, despite it being deemed a minor cross-link within these tendons.
- Conversely, there was no significant relation between the mechanical properties and the levels of either kind of pyridinoline cross-links.
Conclusion and Implications
- Despite Pyrrole being present in low levels, its correlation with high mechanical strength suggests an indirect operative mechanism.
- Uncovering the relationships between Pyrrole cross-links, other matrix characteristics, and tendon material properties could pave the way for identifying horses at risk and developing tailored training practices.
- Further research is needed to understand the specific mode of influence of Pyrrole and other cross-links on tendon strength and potential for injury.
Cite This Article
APA
Thorpe CT, Stark RJ, Goodship AE, Birch HL.
(2011).
Mechanical properties of the equine superficial digital flexor tendon relate to specific collagen cross-link levels.
Equine Vet J Suppl(38), 538-543.
https://doi.org/10.1111/j.2042-3306.2010.00175.x Publication
Researcher Affiliations
- Division of Surgery and Interventional Science, Institute of Orthopaedics and Musculoskeletal Science, RNOHT, University College London, UK.
MeSH Terms
- Animals
- Cadaver
- Collagen / chemistry
- Collagen / physiology
- Horses / physiology
- Spectrophotometry
- Stress, Mechanical
- Tendons / physiology
Citations
This article has been cited 12 times.- Nguyen PK, Jana A, Huang C, Grafton A, Holt I, Giacomelli M, Kuo CK. Tendon mechanical properties are enhanced via recombinant lysyl oxidase treatment.. Front Bioeng Biotechnol 2022;10:945639.
- Ellingson AJ, Pancheri NM, Schiele NR. Regulators of collagen crosslinking in developing and adult tendons.. Eur Cell Mater 2022 Apr 5;43:130-152.
- Busse NI, Gonzalez ML, Krason ML, Johnson SE. β-Hydroxy β-methylbutyrate supplementation to adult Thoroughbred geldings increases type IIA fiber content in the gluteus medius.. J Anim Sci 2021 Oct 1;99(10).
- Wagner FC, Reese S, Gerlach K, Böttcher P, Mülling CKW. Cyclic tensile tests of Shetland pony superficial digital flexor tendons (SDFTs) with an optimized cryo-clamp combined with biplanar high-speed fluoroscopy.. BMC Vet Res 2021 Jun 25;17(1):223.
- Meeremans M, Van de Walle GR, Van Vlierberghe S, De Schauwer C. The Lack of a Representative Tendinopathy Model Hampers Fundamental Mesenchymal Stem Cell Research.. Front Cell Dev Biol 2021;9:651164.
- Eriksen CS, Svensson RB, Gylling AT, Couppé C, Magnusson SP, Kjaer M. Load magnitude affects patellar tendon mechanical properties but not collagen or collagen cross-linking after long-term strength training in older adults.. BMC Geriatr 2019 Jan 31;19(1):30.
- Eekhoff JD, Fang F, Kahan LG, Espinosa G, Cocciolone AJ, Wagenseil JE, Mecham RP, Lake SP. Functionally Distinct Tendons From Elastin Haploinsufficient Mice Exhibit Mild Stiffening and Tendon-Specific Structural Alteration.. J Biomech Eng 2017 Nov 1;139(11):1110031-9.
- Mozdzen LC, Rodgers R, Banks JM, Bailey RC, Harley BA. Increasing the strength and bioactivity of collagen scaffolds using customizable arrays of 3D-printed polymer fibers.. Acta Biomater 2016 Mar;33:25-33.
- Snedeker JG, Gautieri A. The role of collagen crosslinks in ageing and diabetes - the good, the bad, and the ugly.. Muscles Ligaments Tendons J 2014 Jul;4(3):303-8.
- Marturano JE, Xylas JF, Sridharan GV, Georgakoudi I, Kuo CK. Lysyl oxidase-mediated collagen crosslinks may be assessed as markers of functional properties of tendon tissue formation.. Acta Biomater 2014 Mar;10(3):1370-9.
- LaCroix AS, Duenwald-Kuehl SE, Lakes RS, Vanderby R Jr. Relationship between tendon stiffness and failure: a metaanalysis.. J Appl Physiol (1985) 2013 Jul 1;115(1):43-51.
- Marturano JE, Arena JD, Schiller ZA, Georgakoudi I, Kuo CK. Characterization of mechanical and biochemical properties of developing embryonic tendon.. Proc Natl Acad Sci U S A 2013 Apr 16;110(16):6370-5.
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