In situ monitoring of tendon structural changes by elastic scattering spectroscopy:: Correlation with changes in collagen fibril diameter and crimp
In situ monitoring of tendon structural changes by elastic scattering spectroscopy:: Correlation with changes in collagen fibril diameter and crimp
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DOI：
10.1089/ten.2006.12.1821
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发表时间：
2006-07-01
影响因子：
--
通讯作者：
Mudera, Vivek
中科院分区：
文献类型：
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作者：
Morgan, Mary;Kostyuk, Oksana;Mudera, Vivek
本研究的目的是通过弹性散射光谱（ESS）监测兔指屈肌腱在原位和异位加载后的结构变化。光学装置由氙白色光源（λ = 320-860 nm）组成，连接到光纤探针（具有类似于350 μ m的源-检测器间隔）和分光计，由个人计算机（PC）控制。在3种张力方案下原位研究了尸体兔肌腱：未加载（未施加外部张力）、拉伸和1 kg加载，并与切除的肌腱（即，无张力）。四倍以上的光检测在原位卸载肌腱垂直于肌腱长轴比平行于it. Backscatter各向异性表示为各向异性因子（AF（600 nm）：最大的反向散射强度与最小的比值，测量与正交探头位置）。来自不同手指的肌腱之间的背散射各向异性差异不显著。AF（600 nm）对于最不对齐的肌腱准备（切除的肌腱）具有最小值（2.72 +/- 0.38），并且随着施加原位载荷而增加至7.17 +/- 0.54（1 kg载荷）。电子显微镜观察发现，胶原纤维直径的分布变化的负荷施加，与较大的纤维直径减少类似的33%，1公斤负荷相比，切除肌腱。偏振光显微镜显示，在切除的肌腱的特征卷曲模式，但这是很难检测到在卸载肌腱，并没有检测到在原位固定在1公斤的负荷下的肌腱。我们提出，光学各向异性的增加是一个函数的胶原纤维拉直和减少纤维直径的肌腱进行渐进式加载。这些发现对于组织工程师在体内和生物反应器中监测结构是重要的。
The aim of this study was to monitor structural changes in loaded rabbit digital flexor tendons in situ and ex situ via elastic scattering spectroscopy (ESS). The optical setup consisted of a xenon white light source (lambda = 320-860 nm), connected to a fiber optic probe (with a source-detector separation of similar to 350 mu m) and a spectrometer, controlled by a personal computer (PC). Cadaveric rabbit tendons were studied in situ under 3 tensional regimens: unloaded (no extrinsic tension applied), stretched, and 1-kg loaded and compared with excised tendons (i.e., no tension). Four times more light was detected in in situ unloaded tendons perpendicular to the tendon long axis than parallel to it. Backscatter anisotropy was expressed as the anisotropy factor (AF(600nm): ratio of greatest to least backscatter intensity, measured with orthogonal probe positions). Differences in backscatter anisotropy between tendons from different digits were not significant. AF(600nm) had the smallest value (2.72 +/- 0.38) for the least aligned tendon preparations (excised tendons), and increased to 7.17 +/- 0.54 (1-kg loaded) as in situ loads were applied. Electron microscopy revealed that the distribution of collagen fibril diameters changed as loads were applied, with the diameter of larger fibrils decreasing similar to 33% for 1-kg loaded compared with excised tendons. Polarized light microscopy showed a characteristic crimp pattern in excised tendons, but this was hardly detectable in unloaded tendons and not detectable in tendons fixed in situ under a 1-kg load. We propose that the increase in optical anisotropy is a function of collagen fibril straightening and reducing fibril diameter as the tendon undergoes progressive loading. These findings are important for monitoring structure in vivo and in bioreactors for tissue engineers.