The contribution of the pericanalicular matrix to mineral content in human osteonal bone.
The contribution of the pericanalicular matrix to mineral content in human osteonal bone.
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DOI：
10.1016/j.bone.2019.03.018
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发表时间：
2019-06
期刊：
影响因子：
4.1
通讯作者：
A. Roschger;P. Roschger;W. Wagermaier;J. Chen;A. V. van Tol;F. Repp;S. Blouin;A. Berzlanovich;G. Gruber;K. Klaushofer;P. Fratzl;R. Weinkamer
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文献类型：
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作者：
A. Roschger;P. Roschger;W. Wagermaier;J. Chen;A. V. van Tol;F. Repp;S. Blouin;A. Berzlanovich;G. Gruber;K. Klaushofer;P. Fratzl;R. Weinkamer
骨细胞陷窝-小管网络(LCN)穿透骨骼，容纳骨细胞及其突起。尽管LCN的体积分数很低，但它是一个突出的大表面，可能被骨细胞用来与周围的矿化骨基质相互作用，从而有助于矿物质的平衡。这项研究的目的是通过将LCN的局部密度与微米级体积元素中相同位置的矿物质含量在空间上进行关联来定量描述这种贡献。为此，用两种不同的技术对来自健康成人(n= 4)和儿童(n= 2)的65个股骨中段的骨进行了结构表征。用罗丹明染色后，用激光共聚焦扫描显微镜观察LCN在骨内的三维结构。随后的图像分析提供了小管长度密度，即单位体积小管的总长度(μm/μm 3)。利用定量背散射电子成像获得了相同区域矿物含量(wt%Ca)的定量信息，由于LCN孔隙度降低了矿物含量，因此Ca含量与网络密度之间存在负相关关系。计算预测，每−m网络的钙减少约0.97fmolCa。然而，实验表明，65个骨中有62个与此正相关，导致平均每μm小管网状结构的额外钙负荷量为+1.15fmol，即矿物质已在致密网状区积累。我们假设这种堆积发生在小管附近，形成可供骨细胞利用的矿物库。个体间的显著差异表明，库区矿质负荷的大小反映了矿质动态平衡的一个重要参数。
The osteocyte lacunar-canalicular network (LCN) penetrates bone and houses the osteocytes and their processes. Despite its rather low volume fraction, the LCN represents an outstanding large surface that is possibly used by the osteocytes to interact with the surrounding mineralized bone matrix thereby contributing to mineral homeostasis. The aim of this study was to quantitatively describe such contributions by spatially correlating the local density of the LCN with the mineral content at the same location in micrometer-sized volume elements in human osteons. For this purpose, 65 osteons from the femur midshaft from healthy adults (n= 4) and children (n= 2) were structurally characterized with two different techniques. The 3D structure of the LCN in the osteons was imaged with confocal laser scanning microscopy after staining the bone samples with rhodamine. Subsequent image analysis provided the canalicular length density, i.e. the total length of the canaliculi per unit volume (μm/μm3). Quantitative information on the mineral content (wt%Ca) from the identical regions was obtained using quantitative backscattered electron imaging.As the LCN-porosity lowers the mineral content, a negative correlation between Ca content and network density was expected. Calculations predict a reduction of around −0.97 fmol Ca per μm of network. However, the experiment revealed for 62 out of 65 osteons a positive correlation resulting in an average additional Ca loading of +1.15 fmol per μm of canalicular network, i.e. an accumulation of mineral has occurred at dense network regions. We hypothesize that this accumulation happens in the close vicinity of canaliculi forming mineral reservoirs that can be utilized by osteocytes. Significant differences found between individuals indicate that the extent of mineral loading of the reservoir zone reflects an important parameter for mineral homeostasis.