Three-dimensional ultrastructure of osteocytes assessed by focused ion beam-scanning electron microscopy (FIB-SEM)
Three-dimensional ultrastructure of osteocytes assessed by focused ion beam-scanning electron microscopy (FIB-SEM)
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DOI：
10.1007/s00418-018-1645-1
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发表时间：
2018-04-01
影响因子：
2.3
通讯作者：
Amizuka, Norio
中科院分区：
文献类型：
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作者：
Hasegawa, Tomoka;Yamamoto, Tomomaya;Amizuka, Norio
本研究的目的是展示应用聚焦离子束扫描电子显微镜，纤维束扫描电子显微镜揭示干骺端（未成熟）和骨干（成熟）小梁骨细胞胞质突起的三维特征。8周龄雄性小鼠胫骨用醛溶液固定，并在FIB-SEM观察之前进行封闭染色。二维背散射扫描电镜图像显示骨细胞的胞质突起呈碎片状，三维重建的纤维束扫描电镜图像表明，在初级干骺端骨小梁骨细胞随机延长其胞质突起，从而保持与相邻的骨细胞和成骨细胞的接触。与此相反，骨干骨细胞延伸薄的细胞质突起从他们的细胞体，其中运行垂直于骨表面。此外，这些骨细胞的特征是粗突分支成较薄的横向胞质突;然而，在某些时候，这些横突弯曲成直角，垂直于骨表面。成骨细胞还具有较厚的胞质突起，这些突起分支为较薄的突起，然后与相邻骨细胞的胞质突起连接。因此，纤维束扫描电镜是一种有用的技术，用于可视化骨细胞及其胞质过程的三维结构。
The aim of this study is to demonstrate the application of focused ion beam-scanning electron microscopy, FIB-SEM for revealing the three-dimensional features of osteocytic cytoplasmic processes in metaphyseal (immature) and diaphyseal (mature) trabeculae. Tibiae of eight-week-old male mice were fixed with aldehyde solution, and treated with block staining prior to FIB-SEM observation. While two-dimensional backscattered SEM images showed osteocytes' cytoplasmic processes in a fragmented fashion, three-dimensional reconstructions of FIB-SEM images demonstrated that osteocytes in primary metaphyseal trabeculae extended their cytoplasmic processes randomly, thus maintaining contact with neighboring osteocytes and osteoblasts. In contrast, diaphyseal osteocytes extended thin cytoplasmic processes from their cell bodies, which ran perpendicular to the bone surface. In addition, these osteocytes featured thick processes that branched into thinner, transverse cytoplasmic processes; at some point, however, these transverse processes bend at a right angle to run perpendicular to the bone surface. Osteoblasts also possessed thicker cytoplasmic processes that branched off as thinner processes, which then connected with cytoplasmic processes of neighboring osteocytes. Thus, FIB-SEM is a useful technology for visualizing the three-dimensional structures of osteocytes and their cytoplasmic processes.