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

超微结构和组织化学研究主要集中在妊娠16周的小鼠下颌骨髁突的软骨内骨形成部位。破骨细胞在吸收骨领后将细胞突起延伸至软骨基质，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裹钙化软骨基质、细胞碎片和降解的未钙化软骨基质。因此，破骨细胞很可能在没有利用褶皱边界的情况下处理了这些物质。而被认为是透明质酸受体的CD44在这些破骨细胞的细胞表面广泛表达。因此，破骨细胞和软骨中的透明质酸在这个部位发生了相互作用。侵袭的内皮还直接包围了退化的未钙化的软骨基质和少量细胞碎片。此外，附着在侵袭性破骨细胞上的肥大软骨细胞常常包裹着鼻骨钙化的软骨基质。这些发现提示该部位内皮细胞、破骨细胞和肥大的软骨细胞具有未知的独特功能。另一方面，利用这笔赠款，我们对发育小鼠的髁状突软骨和大鼠牙髓进行了免疫组织化学研究，结果已经发表或即将发表。

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.