Vet Comp Orthop Traumatol 2019; 32(S 03): A1-A12
DOI: 10.1055/s-0039-1692237
Podium Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Second Harmonic Generation (SHG) Imaging of Equine Flexor Tendon Fascicular Structure during Healing

S. Durgam
1   Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, United States
,
B. Singh
1   Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, United States
,
M. Brokken
1   Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, United States
,
M. Stewart
2   University of Illinois, Urbana, Illinois, United States
› Author Affiliations
Further Information

Publication History

Publication Date:
17 May 2019 (online)

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    Introduction: Most experimental and clinical studies of equine tendon healing have focused on evaluating longitudinal collagen alignment. The elastic property of energy-storing flexor tendons is largely attributed to higher order structures than fascicular collagen orientation alone. The objective of this study was to evaluate the utility of second harmonic generation (SHG) imaging to assess cross-sectional fascicle architecture of normal and healing equine flexor tendons.

    Materials and Methods: Collagenase-induced tendinitis was created in the superficial digital flexor tendons (SDFT) of eight horses. Horses were euthanized at 6 (n = 4) and 16weeks (n = 4) after collagenase injections and the injured and normal SDFTs were harvested for histological evaluation. Tendon specimens were cross-sectioned and imaged through a confocal microscope with a 2-photon laser source, to generate SHG images. Fascicle bundle sizes were measured from representative cross-sectional images (normal, 6- and 16-week postinjury) and analyzed by one-way ANOVA for repeated measures.

    Results: SHG imaging was very useful to evaluate cross-sectional higher order structure. Tendon fascicle structure was not restored at 16weeks postinjury. Fascicle bundle size was significantly increased at 6 (2-fold) and 16 weeks (3.5-fold) following collagenase injection compared with normal tendon (0.22 ± 0.01 mm2).

    Discussion/Conclusion: The increase in fascicle bundle size between 6 and 16 weeks indicates that normal fascicular dimensions are not restored in the early or intermediate stages of tendon repair and may contribute to the high rates of reinjury. Restricting assessment of tendon histology during healing to longitudinal collagen alignment and crimp restoration alone ignores the considerable importance of higher order reorganization.

    Acknowledgment: AQHA, OSU intramural funded this study.


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    No conflict of interest has been declared by the author(s).