The early mouse 3D osteocyte network in the presence and absence of mechanical loading.
The early mouse 3D osteocyte network in the presence and absence of mechanical loading.
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DOI：
10.1016/j.bone.2012.09.033
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发表时间：
2013
期刊：
影响因子：
4.1
通讯作者：
Yasuyo Sugawara;H. Kamioka;Y. Ishihara;N. Fujisawa;N. Kawanabe;T. Yamashiro
中科院分区：
文献类型：
--
作者：
Yasuyo Sugawara;H. Kamioka;Y. Ishihara;N. Fujisawa;N. Kawanabe;T. Yamashiro
骨细胞被认为是骨中的机械感觉细胞。它们形成一个功能性合胞体，其中它们的过程相互连接，构成一个三维（3D）网络。先前的研究报道，在小鼠中，二维骨细胞网络随着它们的生长而逐渐变得更加规则，尽管在骨生长期间控制骨细胞网络排列的关键因素仍然未知。在这项研究中，我们的特点是骨生长过程中的骨细胞网络的三维形成。据报道，骨骼的形态变化是对机械负荷和卸载的反应。为了评估机械去负荷对骨细胞网络形成的影响，我们对新生小鼠进行坐骨神经切除，以使其左后肢作为去负荷模型。通过用荧光标记的鬼笔环肽对骨细胞的细胞体和突起进行染色来观察骨细胞网络。首先，我们比较了胚胎和6周龄小鼠股骨中的骨细胞网络，以了解正常生长和机械负荷时发生的形态学变化。在胚胎小鼠股骨皮质骨中，骨细胞网络显示出随机的胞体分布，细胞突起的非定向性和不规则形状的细胞。在6周龄的小鼠中，3D网络包含梭形骨细胞，它们平行于股骨的纵轴排列。此外，每个骨细胞放射出更多更长的细胞突起。其次，我们比较了6周龄小鼠的皮质骨细胞网络，有或没有经历坐骨神经切除术，以评估卸载对骨细胞网络形成的影响。机械负荷对皮质骨和松质骨中骨细胞网络的形成均有影响。然而，皮质骨和松质骨之间的网络形成的程度在响应机械载荷方面的方向，核形状和分支形成方面存在差异。
Osteocytes are considered to act as mechanosensory cells in bone. They form a functional synctia in which their processes become interconnected to constitute a three-dimensional (3D) network. Previous studies reported that in mice, the two-dimensional osteocyte network becomes progressively more regular as they grow, although the key factors governing the arrangement of the osteocyte network during bone growth remain unknown. In this study, we characterized the 3D formation of the osteocyte network during bone growth. Morphological skeletal changes have been reported to occur in response to mechanical loading and unloading. In order to evaluate the effect of mechanical unloading on osteocyte network formation, we subjected newborn mice to sciatic neurectomy in order to immobilize their left hind limb as an unloading model. The osteocyte network was visualized by staining osteocyte cell bodies and processes with fluorescently labeled phalloidin. First, we compared the osteocyte network in the femora of embryonic and 6-week-old mice in order to understand the morphological changes that occur with normal growth and mechanical loading. In embryonic mice, the osteocyte network in the femur cortical bone displayed a random cell body distribution, non-directional orientation of cell processes, and irregularly shaped cells. In 6-week-old mice, the 3D network contained spindle-shaped osteocytes, which were arranged parallel to the longitudinal axis of the femur. In addition, more and longer cell processes radiated from each osteocyte. Second, we compared the cortical osteocyte networks of 6-week-old mice that had or had not undergone sciatic neurectomy in order to evaluate the effect of unloading on osteocyte network formation. The osteocyte network formation in both cortical bone and cancellous bone was affected by mechanical loading. However, there were differences in the extent of network formation between cortical bone and cancellous bone in response to mechanical loading with regard to the orientation, nuclear shape and branch formation.