McCreadie Barbara R, Hollister Scott J, Schaffler Mitchell B, Goldstein Steven A
Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, The University of Michigan, G-0161 400 North Ingalls, Ann Arbor, MI 48109-0486, USA.
J Biomech. 2004 Apr;37(4):563-72. doi: 10.1016/S0021-9290(03)00287-2.
Osteocytes have been hypothesized to control the amount and location of bone tissue which is resorbed or formed, based on the strain magnitude they perceive, and therefore may play a role in the bone loss of osteoporosis. The shape of osteocyte lacunae influences the mechanical strain applied to the osteocyte; thus, it is important to quantify their shape to further understand the mechanical environment of this cell. Previous studies of the size and shape of lacunae have been contradictory and limited to two-dimensional measurements on iliac crest biopsies. This investigation measured the size and shape of osteocyte lacunae in trabecular bone near a typical fracture site from three-dimensional image sets obtained by confocal microscopy. Bone tissue specimens were obtained from individuals undergoing hip replacement subsequent to fracture, and matched cadaveric specimens without fracture. After extensive image processing to differentiate the lacunae from the matrix, the volume and anisotropy of the lacuna were determined. No significant difference was found in the size (volume) or shape (anisotropy) of the lacunae between women with and without osteoporotic fracture, although there was a large range of sizes and shapes in both groups. These results suggest that the size or shape of the lacunae, which influences the strain in osteocytes, does not play a role in osteoporotic fracture. In addition, this study provides geometric measures of lacunae that are important in computational modeling of the mechanical environment of osteocytes.
基于骨细胞所感知的应变大小，有假说认为骨细胞可控制被吸收或形成的骨组织的数量和位置，因此可能在骨质疏松症的骨质流失中发挥作用。骨细胞腔隙的形状会影响施加于骨细胞的机械应变；因此，量化其形状对于进一步了解该细胞的机械环境很重要。以往关于腔隙大小和形状的研究结果相互矛盾，且仅限于对髂嵴活检样本进行二维测量。本研究通过共聚焦显微镜获得的三维图像集，测量了典型骨折部位附近小梁骨中骨细胞腔隙的大小和形状。骨组织样本取自骨折后接受髋关节置换的个体，以及匹配的无骨折尸体样本。在进行大量图像处理以将腔隙与基质区分开后，确定了腔隙的体积和各向异性。尽管两组的腔隙大小和形状范围都很大，但在有骨质疏松性骨折和无骨质疏松性骨折的女性之间，腔隙的大小（体积）或形状（各向异性）未发现显著差异。这些结果表明，影响骨细胞应变的腔隙大小或形状在骨质疏松性骨折中不起作用。此外，本研究提供了腔隙的几何测量方法，这在骨细胞机械环境的计算建模中很重要。
