Osteocyte lacunae tissue strain in cortical bone
Osteocyte lacunae tissue strain in cortical bone
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DOI：
10.1016/j.jbiomech.2005.04.032
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发表时间：
2006-01-01
影响因子：
2.4
通讯作者：
Lankford, James
中科院分区：
文献类型：
--
作者：
Nicolella, Daniel P.;Moravits, Donald E.;Lankford, James
目前的理论认为，骨的建模和重建是通过骨细胞介导的信号在细胞水平上进行控制的。然而，骨细胞对特定信号的反应仍不清楚。两种主要的理论是：(1)骨细胞是通过尺周骨基质的机械变形来刺激的；(2)骨细胞是通过流体流动产生的剪应力作用于小管内的骨细胞突起而被刺激的。最近，由于体外实验表明，骨细胞对分析估计的流体剪应力水平的响应比通过在体内测量的骨骼宏观应变水平直接机械拉伸更敏感，因此流体流动理论受到了越来越多的关注。然而，由于骨的复杂的微观组织结构，可能作用于骨细胞的局部楔周组织应变不能从宏观骨应变测量中可靠地估计出来。因此，这项研究的目的是量化由于宏观应用的骨应变在大小上与体内发生的相似的局部楔周骨基质应变。利用数字图像相关应变测量技术，实验测得骨细胞陷窝周围的骨基质应变，宏观应变约为2000微应变，平均明显大于宏观应变，局部可达3万微应变以上的峰值。平均应变集中系数在1.1到3.8之间，这与分析和数值估计一致。这些信息将有助于更好地了解骨细胞如何受到全骨功能负荷的影响。(C)2005年爱思唯尔有限公司。保留所有权利。
Current theories suggest that bone modeling and remodeling are controlled at the cellular level through signals mediated by osteocytes. However, the specific signals to which bone cells respond are still unknown. Two primary theories are: (1) osteocytes are stimulated via the mechanical deformation of the perilacunar bone matrix and (2) osteocytes are stimulated via fluid flow generated shear stresses acting on osteocyte cell processes within canaliculi. Recently, much focus has been placed on fluid flow theories since in vitro experiments have shown that bone cells are more responsive to analytically estimated levels of fluid shear stress than to direct mechanical stretching using macroscopic strain levels measured on bone in vivo. However, due to the complex microstructural organization of bone, local perilacunar bone tissue strains potentially acting on osteocytes cannot be reliably estimated from macroscopic bone strain measurements. Thus, the objective of this study was to quantify local perilacunar bone matrix strains due to macroscopically applied bone strains similar in magnitude to those that occur in vivo. Using a digital image correlation strain measurement technique, experimentally measured bone matrix strains around osteocyte lacunae resulting from macroscopic strains of approximately 2000 microstrain are significantly greater than macroscopic strain on average and can reach peak levels of over 30,000 microstrain locally. Average strain concentration factors ranged from 1.1 to 3.8, which is consistent with analytical and numerical estimates. This information should lead to a better understanding of how bone cells are affected by whole bone functional loading.(c) 2005 Elsevier Ltd. All rights reserved.