Aarden E M, Burger E H, Nijweide P J
Department of Cell Biology, University of Leiden, The Netherlands.
J Cell Biochem. 1994 Jul;55(3):287-99. doi: 10.1002/jcb.240550304.
Although the structural design of cellular bone (i.e., bone containing osteocytes that are regularly spaced throughout the bone matrix) dates back to the first occurrence of bone as a tissue in evolution, and although osteocytes represent the most abundant cell type of bone, we know as yet little about the role of the osteocyte in bone metabolism. Osteocytes descend from osteoblasts. They are formed by the incorporation of osteoblasts into the bone matrix. Osteocytes remain in contact with each other and with cells on the bone surface via gap junction-coupled cell processes passing through the matrix via small channels, the canaliculi, that connect the cell body-containing lacunae with each other and with the outside world. During differentiation from osteoblasts to mature osteocyte the cells lose a large part of their cell organelles. Their cell processes are packed with microfilaments. In this review we discuss the various theories on osteocyte function that have taken in consideration these special features of osteocytes. These are 1) osteocytes are actively involved in bone turnover; 2) the osteocyte network is through its large cell-matrix contact surface involved in ion exchange; and 3) osteocytes are the mechanosensory cells of bone and play a pivotal role in functional adaptation of bone. In our opinion, especially the last theory offers an exciting concept for which some biomechanical, biochemical, and cell biological evidence is already available and which fully warrants further investigations.
尽管骨细胞性骨（即含有在整个骨基质中规则分布的骨细胞的骨）的结构设计可以追溯到骨作为一种组织在进化过程中的首次出现，并且尽管骨细胞是骨中最丰富的细胞类型，但我们目前对骨细胞在骨代谢中的作用了解甚少。骨细胞起源于成骨细胞。它们是由成骨细胞融入骨基质而形成的。骨细胞通过间隙连接耦合的细胞突起彼此保持接触，并与骨表面的细胞保持接触，这些细胞突起通过小通道（即骨小管）穿过基质，骨小管将含有细胞体的骨陷窝彼此连接并与外界相连。在从成骨细胞分化为成熟骨细胞的过程中，细胞失去了大部分细胞器。它们的细胞突起充满了微丝。在这篇综述中，我们讨论了考虑到骨细胞这些特殊特征的关于骨细胞功能的各种理论。这些理论是：1）骨细胞积极参与骨转换；2）骨细胞网络通过其大的细胞 - 基质接触表面参与离子交换；3）骨细胞是骨的机械感觉细胞，在骨的功能适应中起关键作用。我们认为，特别是最后一个理论提供了一个令人兴奋的概念，目前已经有一些生物力学、生物化学和细胞生物学证据支持这一概念，并且完全值得进一步研究。
