Characterization of Microstructural Changes on Biglycan Induced Mice Bone by Low-Field Nuclear Magnetic Resonance.
Characterization of Microstructural Changes on Biglycan Induced Mice Bone by Low-Field Nuclear Magnetic Resonance.
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DOI：
10.31058/j.ap.2021.42004
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
Wang, Xiaodu
中科院分区：
文献类型：
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作者：
Ni, Qingwen;Hua, Rui;Holland, Douglas;Tinajero, Anahi;Han, Yan;Jiang, Jean X;Wang, Xiaodu
采用核磁共振自旋-自旋（T2）弛豫技术测定了大聚糖诱导小鼠骨的孔隙率、结合水分布及其力学性能。低场质子核磁共振技术涉及自旋-自旋弛豫和自由感应衰变（FID）测量，以及衰变数据分析的计算反演方法。CPMG的T2弛豫数据可以反演为T2弛豫分布，然后将T2弛豫分布转化为孔径分布，弛豫时间越长对应的孔隙越大。干燥骨（除去流动水）的FID T2弛豫数据可以反演为T2弛豫分布，然后将该分布转化为结合水成分对应的最长弛豫时间的结合水和固体状水分布。这些技术被应用于定量孔隙度的明显变化，以及在控制和大聚糖敲除小鼠骨骼中的结合水。CPMG T2弛豫的整体骨孔隙度是使用质子弛豫数据除以整体骨体积的校准核磁共振流体体积来确定的。忽略物理样品差异，从反演的FID T2弛豫谱中，利用结合水与固相水组分的比值来标定骨内结合水，结果可用于关联骨力学性能。水化状态显著影响骨的韧性，结合水被认为是预测骨脆性骨折的生物标志物。除了胶原阶段，最近的证据表明，细胞外基质中的蛋白聚糖（pg）的糖胺聚糖（GAGs）也在调节骨的组织水平水化状态中发挥关键作用，从而影响骨的组织水平韧性。此外，在骨报道中，biglycan和decorin是两种主要的pg类型。Biglycan基因敲除引起GAGs、结合水和骨组织韧性的变化。在所有pg亚型中，biglycan被认为是骨矿物基质中的主要亚型。在这项研究中，我们使用了一个biglycan小鼠模型，并通过低场核磁共振测量获得的骨样本，以确定骨孔隙率和结合水的变化，并用于预测敲除biglycan是否会影响结合水的数量，从而导致骨的韧性降低。
A NMR spin-spin (T2) relaxation technique has been described for determining the porosity, and the bound water distribution in biglycan induced mouse bone and correlate to their mechanical properties. The technique of low-field proton NMR involves spin-spin relaxation and free induction decay (FID) measurements, and the computational inversion methods for decay data analysis. The CPMG T2 relaxation data can be inverted to T2 relaxation distribution and this distribution then can be transformed to a pore size distribution with the longer relaxation times corresponding to larger pores. The FID T2 relaxation data of dried bone (mobile water removed) can be inverted to T2 relaxation distribution and this distribution then can be transformed to bound and solid-like water distribution with the longest relaxation time corresponding to bound water component. These techniques are applied to quantify apparent changes in porosity, and bound water in controlled and biglycan knockout mouse bone. Overall bone porosity from CPMG T2 relaxation is determined using the calibrated NMR fluid volume from the proton relaxation data divided by overall bone volume. Ignore the physical sample differences, from the inversion FID T2 relaxation spectrum, the ratio of the bound to solid-like water components is used to calibrate the bound water inside bone, and the results can be used to correlated bone mechanical properties. Hydration status significantly affects the toughness of bone, and bound water has been considered as a biomarker for prediction of bone fragility fractures. In addition to the collagen phase, recent evidence shows that glycosaminoglycans (GAGs) of proteoglycans (PGs) in the extracellular matrix also play a pivotal role in regulating the tissue-level hydration status of bone, there by affecting the tissue-level toughness of bone. Furthermore, biglycan and decorin are two major types of PGs in bone reports. Biglycan knockout induced changes in GAGs, bound water, as well as bone tissue toughness. Among all subtypes of PGs, biglycan is identified as a major subtype in the bone mineral matrix. In this study, we used a biglycan mouse model and the obtained bone samples were measured by low-field NMR to determine the bone porosity and bound water changes, and used to predict if knockout of biglycan may affect the amount of bound water and subsequently lead to reduce toughness of bone.