Compressive loading of the murine tibia reveals site-specific micro-scale differences in adaptation and maturation rates of bone.
Compressive loading of the murine tibia reveals site-specific micro-scale differences in adaptation and maturation rates of bone.
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DOI：
10.1007/s00198-016-3846-6
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发表时间：
2017-03
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影响因子：
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通讯作者：
Windahl SH
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作者：
Bergström I;Kerns JG;Törnqvist AE;Perdikouri C;Mathavan N;Koskela A;Henriksson HB;Tuukkanen J;Andersson G;Isaksson H;Goodship AE;Windahl SH
负荷以部位特异性方式增加骨量和强度;然而，尚未评价负荷对骨基质组成的可能影响。在存在和不存在轴向载荷的情况下，在宏观和微观/分子尺度上分析了小鼠骨的位点特异性结构和材料特性。骨对负荷的反应是异质的，在分子、微观和宏观水平上进行适应。骨质疏松症是一种退行性疾病，导致骨矿物质密度、结构和强度降低。总体目的是探讨这一假设，即负载环境的变化导致小鼠骨中分子/微观和宏观尺度的位点特异性适应。成年小鼠的右胫骨经受明确定义的循环轴向载荷2周;左胫骨用作生理载荷对照。使用μCT（结构）、参考点压痕（材料特性）、拉曼光谱（化学）和小角度X射线散射（矿物结晶和结构）分析骨骼。在对照骨中，胫骨的颅侧和尾侧部位在结构和生化方面不同。作为对负荷的反应，头部和尾部的皮质厚度增加，矿化（分别为-14%和-3%，p < 0.01）和结晶度（分别为-1.4%和-0.3%，p < 0.05）降低。沿着加载骨的长度，胶原蛋白含量在尾部部位变得更加不均匀，并且在两个部位的远端，矿物质/胶原蛋白增加。骨结构和组成是异质的，微调的，自适应的，并在微观尺度上对部位特异性反应，以保持最佳功能。相对于特定的施加载荷，这种异质性的操作可能会影响骨强度。本文的在线版本（doi：10.1007/s 00198 -016-3846-6）包含补充材料，可供授权用户使用。
Loading increases bone mass and strength in a site-specific manner; however, possible effects of loading on bone matrix composition have not been evaluated. Site-specific structural and material properties of mouse bone were analyzed on the macro- and micro/molecular scale in the presence and absence of axial loading. The response of bone to load is heterogeneous, adapting at molecular, micro-, and macro-levels. Osteoporosis is a degenerative disease resulting in reduced bone mineral density, structure, and strength. The overall aim was to explore the hypothesis that changes in loading environment result in site-specific adaptations at molecular/micro- and macro-scale in mouse bone. Right tibiae of adult mice were subjected to well-defined cyclic axial loading for 2 weeks; left tibiae were used as physiologically loaded controls. The bones were analyzed with μCT (structure), reference point indentation (material properties), Raman spectroscopy (chemical), and small-angle X-ray scattering (mineral crystallization and structure). The cranial and caudal sites of tibiae are structurally and biochemically different within control bones. In response to loading, cranial and caudal sites increase in cortical thickness with reduced mineralization (−14 and −3%, p < 0.01, respectively) and crystallinity (−1.4 and −0.3%, p < 0.05, respectively). Along the length of the loaded bones, collagen content becomes more heterogeneous on the caudal site and the mineral/collagen increases distally at both sites. Bone structure and composition are heterogeneous, finely tuned, adaptive, and site-specifically responsive at the micro-scale to maintain optimal function. Manipulation of this heterogeneity may affect bone strength, relative to specific applied loads. The online version of this article (doi:10.1007/s00198-016-3846-6) contains supplementary material, which is available to authorized users.