Collagen V-heterozygous and -null supraspinatus tendons exhibit altered dynamic mechanical behaviour at multiple hierarchical scales
Collagen V-heterozygous and -null supraspinatus tendons exhibit altered dynamic mechanical behaviour at multiple hierarchical scales
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DOI：
10.1098/rsfs.2015.0043
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发表时间：
2016-02-06
期刊：
影响因子：
4.4
通讯作者：
Soslowsky, Louis J.
中科院分区：
文献类型：
--
作者：
Connizzo, Brianne K.;Han, Lin;Soslowsky, Louis J.
肌腱的功能使用一组独特的机械性能，由细胞外基质及其对不同的多轴载荷的响应能力决定。在临床和动物研究中，胶原V表达的减少，例如在经典的Ehlers-Danlos综合征中，导致原纤维形态改变和宏观机械功能改变，但原纤维水平的变化导致宏观功能变化的机制尚未研究。本研究通过定义野生型、胶原V杂合和无胶原V冈上肌肌腱的多尺度机械响应来解决这一问题。对肌腱进行机械测试并分析宏观尺度性能以及微观尺度（纤维重新排列）和纳米尺度（原纤维变形和滑动）响应。在许多宏观尺度参数中，结果显示了剂量依赖性反应，无效组的性质严重降低。此外，杂合和无效组响应负荷快于野生型肌腱通过早期的纤维重新排列和原纤维拉伸。然而，杂合组表现出增加的原纤维滑动，而无效组表现出无原纤维滑动。这些研究表明，动态反应在确定整体功能中起着重要作用，胶原V是这些关系发展中的关键调节剂。
Tendons function using a unique set of mechanical properties governed by the extracellular matrix and its ability to respond to varied multi-axial loads. Reduction of collagen V expression, such as in classic Ehlers-Danlos syndrome, results in altered fibril morphology and altered macroscale mechanical function in both clinical and animal studies, yet the mechanism by which changes at the fibril level lead to macroscale functional changes has not yet been investigated. This study addresses this by defining the multiscale mechanical response of wild-type, collagen V-heterozygous and -null supraspinatus tendons. Tendons were subjected to mechanical testing and analysed for macroscale properties, as well as microscale (fibre re-alignment) and nanoscale (fibril deformation and sliding) responses. In many macroscale parameters, results showed a dose-dependent response with severely decreased properties in the null group. In addition, both heterozygous and null groups responded to load faster than in wild-type tendons via earlier fibre realignment and fibril stretch. However, the heterozygous group exhibited increased fibril sliding, while the null group exhibited no fibril sliding. These studies demonstrate that dynamic responses play an important role in determining overall function and that collagen V is a critical regulator in the development of these relationships.