Functions of endothelium osteoclasts and hypertrophic chondrocytes in early phase of endochondral ossification

本文对孕16天小鼠下颌骨髁状突软骨内成骨的起始部位进行了超微结构和组织化学研究。破骨细胞吸收骨领后，将其细胞突起延伸到软骨基质中，并与肥大的软骨细胞接触。这些破骨细胞通过细胞突起或空泡结构包埋钙化的软骨基质、细胞碎片和降解的未钙化的软骨基质。因此，破骨细胞可能不利用皱褶边界处理这些物质。而透明质酸受体CD44广泛存在于破骨细胞表面。因此，破骨细胞和透明质酸之间的相互作用，在软骨建议在这个网站。侵入的内皮细胞也直接包围着降解的未钙化的软骨基质和细胞碎片的小沉积物。另外，肥大的软骨细胞附着在破骨细胞上，常包绕着钙化的软骨基质。这些发现提示了该部位的内皮细胞、破骨细胞和肥大软骨细胞的未知的独特功能。另一方面，利用该基金，我们对发育中的小鼠髁突软骨和大鼠牙髓进行了免疫组织化学研究，结果已发表或即将发表。

Ultrastructural and histochemical studies ware undertaken focused on the initial endochondral bone formation site in the mouse mandibular condyle of clay 16 of pregnancy. After resorbing the bone collar, the osteoclasts extended their cell processes into cartilage matrix and made contact with hypertrophic chondrocytes. By means of cell process or vacuolar structures, these osteoclasts entrapped the calcified cartilage matrices, cell debris, and the degraded uncalcified cartilage matrices. Thus, osteoclasts probably disposed of these substances without utilizing ruffled borders. While, CD44 that is considered as hyaluronan receptor was extensively detected on the cell surfaces of these osteoclasts. Therefore, an interaction between osteoclasts and hyaluronan in the cartilage was suggested at this site. Invading endotheliun also directly surrounded degraded uncalcified cartilage matrices and small deposits of cell debris. In addition, hypertrophic chondrocytes that had attached to the invading osteoclasts often enclosed the snall calcified cartilage matrices. These findings suggest unknown unique functions of endothelium, osteoclasts, and hypertrophic chondrocytes at this site.On the other hand using this grant, we executed immunohistochemical study of developmental muse condylar cartilage and rat dental pulp, and results were published or will nearly be published.