Determining the contribution of glycosaminoglycans to tendon mechanical properties with a modified shear-lag model
Determining the contribution of glycosaminoglycans to tendon mechanical properties with a modified shear-lag model
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DOI：
10.1016/j.jbiomech.2013.07.008
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发表时间：
2013-09-27
影响因子：
2.4
通讯作者：
Shenoy, Vivek B.
中科院分区：
文献类型：
--
作者：
Ahmadzadeh, Hossein;Connizzo, Brianne K.;Shenoy, Vivek B.
肌腱具有复杂的分级结构，由胶原和非胶原基质组成。尽管有几项研究旨在阐明基质组分之间的负荷转移机制，但糖胺聚糖（GAG）的作用仍存在争议。因此，本研究调查的弹性性能的肌腱使用修改后的剪切滞后模型，占的结构和非线性力学响应的GAGs。与以前的剪切滞后模型，无论是在二维或轴对称的几何形状解决，我们提出了一个封闭形式的分析模型，三维周期性晶格的原纤维连接的GAG。使用这种方法，我们表明，非线性力学响应的GAGs导致一个独特的脚趾区域的应力应变响应的肌腱。趾部区域的临界应变被示出为与原纤维长度成反比地减小。此外，我们确定了与微观结构参数（例如，GAG间距、刚度和几何形状）相关的特征长度尺度，在该尺度上负载从GAG转移到原纤维。我们发现，当原纤维长度显着大于这个长度尺度，肌腱的机械性能是相对不敏感的删除GAG。我们的研究结果提供了一个物理解释的不敏感性的机械反应的肌腱删除GAGs在成熟的肌腱，强调的重要性，原纤维长度在确定肌腱的弹性性能，并与计算密集的模拟非常一致。(C)2013爱思唯尔有限公司保留所有权利。
Tendon has a complex hierarchical structure composed of both a collagenous and a non-collagenous matrix. Despite several studies that have aimed to elucidate the mechanism of load transfer between matrix components, the roles of glycosaminoglycans (GAGs) remain controversial. Thus, this study investigated the elastic properties of tendon using a modified shear-lag model that accounts for the structure and non-linear mechanical response of the GAGs. Unlike prior shear-lag models that are solved either in two dimensions or in axially symmetric geometries, we present a closed-form analytical model for three-dimensional periodic lattices of fibrils linked by GAGs. Using this approach, we show that the non-linear mechanical response of the GAGs leads to a distinct toe region in the stress-strain response of the tendon. The critical strain of the toe region is shown to decrease inversely with fibril length. Furthermore, we identify a characteristic length scale, related to microstructural parameters (e.g. GAG spacing, stiffness, and geometry) over which load is transferred from the GAGs to the fibrils. We show that when the fibril lengths are significantly larger than this length scale, the mechanical properties of the tendon are relatively insensitive to deletion of GAGs. Our results provide a physical explanation for the insensitivity for the mechanical response of tendon to the deletion of GAGs in mature tendons, underscore the importance of fibril length in determining the elastic properties of the tendon, and are in excellent agreement with computationally intensive simulations. (C) 2013 Elsevier Ltd. All rights reserved.