Reduction of fibrillar strain-rate sensitivity in steroid-induced osteoporosis linked to changes in mineralized fibrillar nanostructure.
Reduction of fibrillar strain-rate sensitivity in steroid-induced osteoporosis linked to changes in mineralized fibrillar nanostructure.
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DOI：
10.1016/j.bone.2019.115111
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发表时间：
2019-11
期刊：
影响因子：
4.1
通讯作者：
L. Xi;L. Xi;P. D. Falco;P. D. Falco;E. Barbieri;A. Karunaratne;L. Bentley;C. T. Esapa;G. R. Davis;Nicholas J. Terrill;R. Cox;N. Pugno;N. Pugno;N. Pugno;R. V. Thakker;R. Weinkamer;Wenwang Wu;D. Fang;D. Fang;H. S. Gupta
中科院分区：
文献类型：
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作者：
L. Xi;L. Xi;P. D. Falco;P. D. Falco;E. Barbieri;A. Karunaratne;L. Bentley;C. T. Esapa;G. R. Davis;Nicholas J. Terrill;R. Cox;N. Pugno;N. Pugno;N. Pugno;R. V. Thakker;R. Weinkamer;Wenwang Wu;D. Fang;D. Fang;H. S. Gupta
由于骨是在动态力学环境中使用的，因此了解其时间依赖性力学行为的结构起源以及代谢性骨病的变化是有意义的。然而，在矿化纤维基质的尺度（纳米级），应变率依赖力学的性质是不完全理解。在这里，我们调查的原纤维和矿物变形行为的小鼠模型的库欣综合征，用于了解类固醇引起的骨质疏松症，使用同步辐射小角和广角散射/衍射结合内situtensive测试在三个应变率范围从10- 4到10- 1 s-1。我们发现，有效的原纤维和矿物模量和原纤维重取向显示没有显着增加应变率在骨化骨，但增加显着的正常（野生型）骨。通过应用骨基质变形的纤维-板层两级结构模型来拟合结果，我们得到的迹象表明，改变胶原-矿物质相互作用在纳米级-沿着改变纤维取向分布-可能是这种改变应变率敏感性的根本原因。我们的研究结果表明，骨质疏松症中骨基质的应变率敏感性改变可能是导致此类代谢性骨疾病中机械能力降低的因素之一，并且增加这种敏感性可能会改善生物力学性能。
As bone is used in a dynamic mechanical environment, understanding the structural origins of its time-dependent mechanical behaviour – and the alterations in metabolic bone disease – is of interest. However, at the scale of the mineralized fibrillar matrix (nanometre-level), the nature of the strain-rate dependent mechanics is incompletely understood. Here, we investigate the fibrillar- and mineral-deformation behaviour in a murine model of Cushing’s syndrome, used to understand steroid induced osteoporosis, using synchrotron small- and wide-angle scattering/diffraction combined within situtensile testing at three strain rates ranging from 10-4to 10-1s-1. We find that the effective fibril- and mineral-modulus and fibrillar-reorientation show no significant increase with strain-rate in osteoporotic bone, but increase significantly in normal (wild-type) bone. By applying a fibril-lamellar two-level structural model of bone matrix deformation to fit the results, we obtain indications that altered collagen-mineral interactions at the nanoscale – along with altered fibrillar orientation distributions – may be the underlying reason for this altered strain-rate sensitivity. Our results suggest that an altered strain-rate sensitivity of the bone matrix in osteoporosis may be one of the contributing factors to reduced mechanical competence in such metabolic bone disorders, and that increasing this sensitivity may improve biomechanical performance.