Kureshi Alvena, Vaiude Partha, Nazhat Showan N, Petrie Aviva, Brown Robert A
University College London, Tissue Repair & Engineering Centre, Institute of Orthopaedics, Stanmore Campus, London HA7 4LP, UK.
J Biomech. 2008 Dec 5;41(16):3462-8. doi: 10.1016/j.jbiomech.2008.08.018. Epub 2008 Nov 13.
Inguinal herniation represents a common condition requiring surgical intervention. Despite being regarded as a connective tissue disorder of uncertain cause, research has focused predominantly on biochemical changes in the key tissue layer, the transversalis fascia (TF) with little direct analysis of functional tissue mechanics. Connective tissue tensile properties are dominated by collagen fibril density and architecture. This study has correlated mechanical properties of herniated TF (HTF) and non-herniated TF (NHTF) with fibrillar properties at the ultrastructural level by quasi-static tensile mechanical analysis and image analysis of collagen electron micrographs. No significant difference was found between any of the key mechanical properties (break stress, strain or modulus) for HTF and NHTF. In addition, no significant differences were found in average collagen fibril diameter, density or fibre bundle spacing. However, both groups displayed anisotropy with greater break stress (p=0.001) on average in the transverse anatomical plane compared to the longitudinal plane in a mean ratio of 2:1 (anisotropy ratio), though there was no evidence of a difference in this ratio for HTF and NHTF for both break stress and modulus. It was noted that this anisotropy ratio corresponds closely with the expected force distribution on a model cylindrical structure loaded axially. The absence of other functional differences does not support the idea of a failing (injured) tissue but is consistent with it being a tissue undergoing chronic growth/expansion under multi-vectored mechanical loading. These findings provide new clues to collagen tissue herniation for mathematical modelling and model tissue engineering.
腹股沟疝是一种需要手术干预的常见病症。尽管它被视为一种病因不明的结缔组织疾病，但研究主要集中在关键组织层——腹横筋膜（TF）的生化变化上，而对功能性组织力学的直接分析较少。结缔组织的拉伸特性主要由胶原纤维密度和结构决定。本研究通过准静态拉伸力学分析和胶原电子显微镜图像分析，将疝出的TF（HTF）和未疝出的TF（NHTF）的力学性能与超微结构水平的纤维特性相关联。HTF和NHTF的任何关键力学性能（断裂应力、应变或模量）之间均未发现显著差异。此外，平均胶原纤维直径、密度或纤维束间距也未发现显著差异。然而，两组均表现出各向异性，在横向解剖平面上的平均断裂应力（p=0.001）高于纵向平面，平均比例为2:1（各向异性比例），尽管对于HTF和NHTF的断裂应力和模量，该比例没有差异的证据。值得注意的是，这种各向异性比例与轴向加载的模型圆柱形结构上的预期力分布密切相关。其他功能差异的缺乏并不支持组织衰竭（损伤）的观点，但与它是一种在多向量机械负荷下经历慢性生长/扩张的组织相一致。这些发现为胶原组织疝的数学建模和模型组织工程提供了新的线索。
