The role of cartilage canals in endochondral and perichondral bone formation:: are there similarities between these two processes?
The role of cartilage canals in endochondral and perichondral bone formation:: are there similarities between these two processes?
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DOI：
10.1111/j.1469-7580.2005.00404.x
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发表时间：
2005-04-01
影响因子：
2.4
通讯作者：
Fritsch, H
中科院分区：
文献类型：
--
作者：
Blumer, MJF;Longato, S;Fritsch, H
我们对软骨管的发育进行了研究，以阐明它们在骨形成过程中的作用。软骨管是含有血管的管子，这些血管在次级骨化中心(SOC)形成之前发现于透明软骨中。它们的确切作用仍然存在争议，目前还不清楚它们是否在SOC出现时促进了软骨内骨的形成。我们观察了不同发育阶段(E20、D2、5、7、8、10和13)鸡股骨的软骨管。通过三维重建、光镜、电子显微镜、组织化学和免疫组织化学[血管内皮生长因子(VEGF)、I型和II型胶原]等方法对股骨进行了三维重建、光镜、电子显微镜和免疫组织化学研究。胚胎最后一天(E20)首次可见SOC。软骨管是带血管的软骨膜及其间充质干细胞层进入透明软骨的延伸。根管在骨膜内形成复杂的网状结构，有些根管盲端穿透SOC。血管内皮生长因子促进了根管向SOC的生长。随着开发的进行，SOC的规模越来越大，邻近的运河也被并入其中。根管内含有破骨细胞，使肥大的软骨细胞裂开陷窝，随后间充质细胞侵入陷窝，形成类骨层。在较老的阶段，这一层矿化，并通过增加更多的细胞而增加厚度。在SOC外，软骨管被类骨质包围，类骨质是通过软骨膜成骨过程形成的。我们得出结论，软骨管对软骨膜和软骨内骨的形成都有贡献，成骨细胞在这两个过程中具有相同的来源。
We investigated the development of cartilage canals to clarify their function in the process of bone formation. Cartilage canals are tubes containing vessels that are found in the hyaline cartilage prior to the formation of a secondary ossification centre (SOC). Their exact role is still controversial and it is unclear whether they contribute to endochondral bone formation when an SOC appears. We examined the cartilage canals of the chicken femur in different developmental stages (E20, D2, 5, 7, 8, 10 and 13). To obtain a detailed picture of the cellular and molecular events within and around the canals the femur was investigated by means of three-dimensional reconstruction, light microscopy, electron microscopy, histochemistry and immunohistochemistry [vascular endothelial growth factor (VEGF), type I and II collagen]. An SOC was visible for the first time on the last embryonic day (E20). Cartilage canals were an extension of the vascularized perichondrium and its mesenchymal stem cell layers into the hyaline cartilage. The canals formed a complex network within the epiphysis and some of them penetrated into the SOC were they ended blind. The growth of the canals into the SOC was promoted by VEGF. As the development progressed the SOC increased in size and adjacent canals were incorporated into it. The canals contained chondroclasts, which opened the lacunae of hypertrophic chondrocytes, and this was followed by invasion of mesenchymal cells into the empty lacunae and formation of an osteoid layer. In older stages this layer mineralized and increased in thickness by addition of further cells. Outside the SOC cartilage canals are surrounded by osteoid, which is formed by the process of perichondral bone formation. We conclude that cartilage canals contribute to both perichondral and endochondral bone formation and that osteoblasts have the same origin in both processes.