Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX,
Eur Cell Mater. 2018 Feb 13;35:87-102. doi: 10.22203/eCM.v035a07.
BiTendons are constructed from collagenous fascicles separated by endotenon/interfascicular matrix (IFM). Tendons may be specialised for precision movement or to store energy during locomotion and for the latter the elasticity of the endotenon/IFM is particularly important. The equine superficial digital flexor tendon (SDFT) is a dedicated energy-storing tendon with a similar function to the human Achilles tendon. Classical anatomical descriptions portray fascicles as longitudinally arranged distinct anatomical structures. In the present study, using three-dimensional reconstruction from whole tissue slices and histological sections, the fascicles of the equine SDFT were found to adopt a complex interweaved arrangement. Fascicles were found to fully and partially converge and diverge within the tendon and fascicle bundles were observed. Fascicle morphology was not homogenous with narrowing, broadening and twisted fascicles observed in addition to relatively straight fascicles. The number of fascicle bundles observed in cross-section increased from the proximal to the distal end of the tendon, whilst the number of fascicles decreased with age in the proximal region. Fascicular patterns were not similar between the left and right limbs, across different regions or at different ages. A decrease in thickness of the endotenon/IFM between fascicles with age was found in the distal tendon region. The results provide a rationale for considering fascicular organisation when diagnosing and treating tendon injuries, for bioengineering tendon and when modelling tendon function.
双纤维肌腱由胶原纤维束组成，纤维束之间由内膜/束间基质（IFM）分隔。肌腱可能专门用于精确运动，或者在运动过程中储存能量，对于后者，内膜/IFM 的弹性尤为重要。马的浅层指屈肌腱（SDFT）是一种专门的储能肌腱，其功能类似于人类的跟腱。经典的解剖学描述将纤维束描绘为沿纵向排列的独特解剖结构。在本研究中，通过对整个组织切片和组织学切片进行三维重建，发现马的 SDFT 纤维束采用复杂的交织排列。在肌腱内，纤维束被发现完全和部分汇聚和发散，并且观察到纤维束束。纤维束形态不均匀，除了相对较直的纤维束外，还观察到变窄、变宽和扭曲的纤维束。在横截面上观察到的纤维束束数量从肌腱的近端向远端增加，而在近端区域，随着年龄的增长，纤维束的数量减少。左右肢体之间、不同区域之间或不同年龄之间的纤维束模式并不相似。随着年龄的增长，在远端肌腱区域发现内膜/IFM 厚度在纤维束之间减少。研究结果为在诊断和治疗肌腱损伤、生物工程肌腱以及模拟肌腱功能时考虑纤维束组织提供了依据。
