Department of Biomedical Engineering, Lund University, PO Box 118, 221 00, Lund, Sweden.
Department of Applied Physics, University of Eastern Finland, 702 11, Kuopio, Finland.
J Bone Miner Metab. 2020 May;38(3):289-298. doi: 10.1007/s00774-019-01068-y. Epub 2019 Dec 5.
The composite nature of bone as a material governs its structure and mechanical behavior. How the collagenous matrix mineralizes, in terms of both mineral deposition and structure of the mineral crystals, is highly interesting when trying to elucidate the complex structural changes that occur during bone growth and maturation. We have previously looked at mineral deposition and structural evolution of the collagenous matrix, linking both to changes in mechanics. The purpose of this study was to provide specific information on changes in crystal size and organization as a function of growth and maturation.
Using micro-computed tomography (µCT) and micro-focused scanning small-angle X-ray scattering (SAXS) we investigated cortical bone in two orthogonal directions relative to the long axis of the humeri of New Zealand White rabbits spanning from new-born to 6-months of age. We also investigated the changes with tissue age by looking at radial profiles of osteonal structures in the 6-months old rabbits. The findings were compared to our previous compositional, structural and mechanical data on the same sample cohort.
µCT showed a continuous mineral deposition up until 3-months of age, whilst the SAXS data showed an increase in both crystal thickness and degree of orientation up until 6-months of age. The osteonal profiles showed no statistically significant changes in crystal thickness.
Comparison to previously collected mechanical data suggests that changes are not only explained by amount of mineral in the tissue but also by the crystal dimensions.
骨骼作为一种材料，其复合性质决定了它的结构和机械性能。当试图阐明在骨骼生长和成熟过程中发生的复杂结构变化时，胶原基质的矿化方式（包括矿物质沉积和矿物质晶体结构）非常有趣。我们之前已经研究了胶原基质的矿物质沉积和结构演变，并将两者与力学变化联系起来。本研究的目的是提供有关晶体尺寸和组织随生长和成熟变化的具体信息。
使用微计算机断层扫描（µCT）和微聚焦扫描小角 X 射线散射（SAXS），我们研究了新西兰白兔肱骨长轴两个正交方向的皮质骨，涵盖了从新生到 6 个月大的年龄。我们还通过观察 6 个月大的兔子的骨单位结构的径向分布来研究组织年龄的变化。将这些发现与我们之前对同一样本队列的组成、结构和力学数据进行了比较。
µCT 显示直到 3 个月大时，矿物质沉积持续增加，而 SAXS 数据显示直到 6 个月大时，晶体厚度和取向程度都增加了。骨单位形态显示晶体厚度没有统计学上的显著变化。
与之前收集的力学数据进行比较表明，变化不仅可以通过组织中的矿物质含量来解释，还可以通过晶体尺寸来解释。
