Morphological examination during in vitro cartilage formation by human mesenchymal stem cells
Morphological examination during in vitro cartilage formation by human mesenchymal stem cells
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DOI：
10.1007/s00441-005-1140-6
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发表时间：
2005-11-01
影响因子：
3.6
通讯作者：
Sekiya, I
中科院分区：
文献类型：
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作者：
Ichinose, S;Tagami, M;Sekiya, I
通过软骨内骨化形成骨骼是发育过程中最复杂的过程之一。解决这种复杂性的一种方法是检查简化的系统。当细胞作为微团培养时，观察到间充质干细胞（MSC）的体外软骨形成。一些研究已经证实了分子事件，显示了这些细胞作为分化模型的有用性。我们已经阐明了软骨形成的过程中，骨髓间充质干细胞从形态学的角度来看，光镜和透射电镜和免疫组化检查。MSC的形态从球形变为纺锤形，并且细胞在第1天聚集并形成连接复合物。第7天，观察到三层。浅带由数层具有连接复合体的细长细胞组成。中层由凋亡小体组成，深层由分泌细胞外基质的软骨细胞样细胞占据。第14天，中间区消失，软骨陷窝内检测到深层区的软骨细胞样细胞。它们被含有I型、II型和X型胶原和硫酸软骨素的软骨基质覆盖。到第21天，由梭形细胞组成的外层在某些地方消失了。随着丹药的生长，外层似乎无法拉伸，无法保持对丹药的恒定覆盖。因此，我们的研究结果表明，MSC在分化过程中根据其微环境改变其形态。MSC体外软骨形成使得有可能澄清软骨发生过程中发生的详细形态学事件。
The formation of the skeleton through endochondral ossification is one of the most complex processes in development. One approach to resolving this complexity is to examine simplified systems. In vitro cartilage formation by mesenchymal stem cells (MSCs) is observed when the cells are cultured as a micromass. Several studies have confirmed the molecular events, showing the usefulness of these cells as a differentiation model. We have elucidated the process of cartilage formation in MSCs from the morphological point of view by light and transmission electron microscopy and immunohistochemical examination. The morphology of the MSCs changed from spherical to spindle-shaped, and the cells aggregated and formed junctional complexes during Day 1. At Day 7, three layers were observed. The superficial zone consisted of several layers of elongated cells with junctional complexes. The middle zone was composed of apoptotic bodies, and the deep zone was occupied by chondrocyte-like cells excreting extracellular matrices. At Day 14, the middle zone had disappeared, and the chondrocyte-like cells in the deep zone were detected within cartilage lacuna. They were covered by cartilage matrices containing collagen types I, II, and X and chondroitin sulfate. By Day 21, the outer layer consisting of spindle-shaped cells had disappeared in places. As the pellet grew, the outer layer seemed to be unable to stretch to maintain a constant covering around the pellet. Our findings have thus revealed that MSCs change their morphology depending upon their microenvironment during differentiation. In vitro cartilage formation by MSCs makes it possible to clarify the detailed morphological events that occur during chondrogenesis.