A preliminary technical study on sodium dodecyl sulfate-induced changes of the nano-structural and macro-mechanical properties in human iliotibial tract specimens
A preliminary technical study on sodium dodecyl sulfate-induced changes of the nano-structural and macro-mechanical properties in human iliotibial tract specimens
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DOI：
10.1016/j.jmbbm.2016.01.018
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发表时间：
2016-08-01
影响因子：
3.9
通讯作者：
Scheidt, Holger A.
中科院分区：
文献类型：
--
作者：
Hammer, Niels;Huster, Daniel;Scheidt, Holger A.
脱细胞支架常用于外科修复韧带和肌腱。尽管已有与脱细胞化过程相关的宏观力学性能数据，但仍缺乏相应的纳米结构性能数据。这些数据将有助于识别形成的细胞外基质中被脱细胞化化学改变的靶蛋白。在这项研究中，我们通过比较天然和非细胞髂胫束样本胶原的分子特性和宏观应力应变行为来研究结构的改变。材料和方法：从5个供体（平均年龄28.2±4.7岁）获得5对匹配的人髂胫束样本。使用1vol %十二烷基硫酸钠（SDS）进行7天的脱细胞处理。利用C-13魔角旋转核磁共振波谱（C-13 CP MAS NMR）比较了胶原蛋白的整体二级结构和胶原典型氨基酸蛋白的内部动力学。所得到的数据与年龄匹配的应力应变数据在单轴拉伸装置和组织学上获得的呼吸道样本进行了比较。结果：在SDS脱细胞前后的束样品中发现了典型且几乎相同的胶原C-13 CP MAS NMR谱。在原生和脱细胞样品中，胶原蛋白主干保持完整。在这两种情况下，胶原蛋白的分子组成基本没有改变。此外，氨基酸Hyp γ、Pro α /Hyp α、Ala α、Gly α和Ala β也有类似的动态行为。这些与SDS脱细胞化相关的胶原分子特性的微小变化与宏观力学拉伸行为（如弹性模量和极限应力）的类似微小变化一致。组织学显示完整的I型胶原，脱细胞前后微量的弹性蛋白，脱细胞诱导的蛋白聚糖减少的证据。讨论：通过分子组成和动力学表明，SDS处理对胶原的纳米结构特性有细微的影响。髂胫束样品中胶原分子结构特性的缺乏脱细胞化相关变化与其宏观力学拉伸行为的微小变化是一致的。尽管给定的设置从力学测试的两个尺度极端接近软组织力学，但需要在更大的样本量中进一步进行结构分析以证实这些发现。(C) 2016 Elsevier Ltd.版权所有。
Introduction: Acellular scaffolds are frequently used for the surgical repair of ligaments and tendons. Even though data on the macro-mechanical properties related to the acellularization process exist, corresponding data on the nano-structural properties are still lacking. Such data would help identify target proteins of the formed extracellular matrix that are chemically altered by the acellularization. In this study we examined the altered structure by comparing molecular properties of collagens from native and acellular iliotibial tract samples to the macroscopic stress strain behavior of tract samples.Material and methods: Matched pairs of five human iliotibial tract samples were obtained from five donors (mean age 28.2 +/- 4.7 years). One of each pair was acellularized using 1 vol% sodium dodecyl sulfate (SDS) for 7 days. C-13 magic angle spinning nuclear magnetic resonance spectroscopy (C-13 CP MAS NMR) was utilized to compare the collagen overall secondary structure and internal dynamics of collagen-typical amino acid proteins. The resulting data was compared to age-matched stress strain data of tract samples obtained in an uniaxial tensile setup and histologically.Results: Typical and nearly identical collagen C-13 CP MAS NMR spectra were found in the tract samples before and after acellularization with SDS. The characteristic collagen backbone remained intact in the native and acellular samples. Collagen molecular composition was largely unaltered in both conditions. Furthermore, a similar dynamic behavior was found for the amino acids Hyp gamma, Pro alpha/Hyp alpha, Ala alpha, Gly alpha and Ala beta. These minute alterations in the collagens' molecular properties related to acellularization with SDS were in line with the similarly minute changes in the macro-mechanical tensile behavior, such as the elastic modulus and ultimate stress. Histology showed intact type I collagens, minute amounts of elastins before and after acellularization and evidence for acellularization-induced reductions of proteoglycans.Discussion: Nano-structural properties of collagens are minutely affected by SDS treatment for acellularization, indicated by the molecular composition and dynamics. The lacking acellularization-related changes in the molecular structure properties of collagens in iliotibial tract samples are in line with the small alterations in their macro-mechanical tensile behavior. Though the given setup approaches soft tissue mechanics from both scaling extremes of mechanical testing, further structural analyzes are needed in a larger sample size to substantiate these findings. (C) 2016 Elsevier Ltd. All rights reserved.