Molecullar Biology on the Calcification of Cartilages and Tooth Germs in Vito.

1)梅克尔软骨命运的研究。梅克尔软骨软骨细胞在体外合成骨钙素、骨桥蛋白、I型胶原等骨型标记蛋白时，可表达骨细胞表型。将Meckel软骨中间部分细分为前、后两个区域。我们的结果表明，在梅克尔软骨中间部分的细胞有两种不同的可能的命运。前部被trap阳性细胞溶解，而后部中部的软骨细胞通过表型转化直接转化为成纤维细胞。2)啮齿动物磨牙无牙釉质区发育的研究采用原位杂交和免疫组织化学方法研究了大鼠磨牙中淀粉原蛋白mRNA的表达和分泌情况。我们的研究结果表明，无牙釉质区细胞分化为分泌成釉素的细胞，即成釉细胞，但在牙齿发育的早期，这种分化只持续很短的时间。在牙齿发育的早期阶段，淀粉原蛋白在内牙釉质上皮中的作用可能会在未来出现。3)牙骨质体外形成的研究。建立了一种用于小鼠磨牙牙骨质形成体外研究的新器官培养体系。这种培养方法保持了牙胚的三维结构。培养第43天，脱细胞牙骨质上形成了与牙周韧带本身明显不同的脱细胞牙骨质样层。

1) The study on the fate of Meckel's cartilage.The Meckel's cartilage chondrocytes can express the osteocytic phenotype in vitro during synthesis of bone-type marker proteins such as osteocalcin, osteopontin and type I collagen. The midportion of Meckel's cartilage was subdivided into two regions, the anterior and posterior regions.The our results suggest that cells in the midportion of Meckels cartilage have two different possible fates. The anterior is dissolved by TRAP-positive cells, while chondrocytes in the posterior midportion are transformed directly into fibroblastic cells by phenotypic conversion.2) The study on the development of enanamel-free area of rodent molarsBoth the expression of amelogenin mRNA and secretion of amelogenin were investigated in rat molars by in situ hybridization and immunohistohemistry.Our results suggest that enamel-free area cells differentiated into amelogenin secreting cells, I.e. ameloblasts, but that the seretion lasts for only a short period at the early stage of tooth development. A role for amelogenin in inner enamel epithelium at the early stage of tooth development may emerge in the future.3)The study on the formation of cementum in vitro.A new organ culture system for in vitro study of cementogenesis in mouse molars teeth was developed. This culture method maintained the three-dimensional architecture of tooth germ. By the 43rd culture day, acellular cementum-like layer, clearly different from the periodontal ligament proper, was formed on the acellular cementum.