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Histochemical and Immunohistochemical Studies on the Mechanisms of Calcium Regulation by Dental and Periodontal Hard Tissue-Forming Cells (1993)

牙齿和牙周硬组织形成细胞钙调节机制的组织化学和免疫组织化学研究 (1993)

基本信息

批准号：
04404069
负责人：
TAKANO Yoshiro
金额：
$ 17.92万
依托单位：
NIIGATA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

In order to elucidate the mechanisms whereby cells of the dental and periodontal mineralized tissue-forming cells regulate calcium, our research group introduced a new method to reveal possible Ca-binding sites in cell layrs by vascularly perfusing animals with a high Ca-containing solution followed by anhydrous tissue processing for light and electron microscopy and X-ray microanalysis. With this method we found granular precipitates of Ca-phosphate to occur exclusively in the ameloblasts at the stage of matrix formation, and the smooth-ended maturation ameloblasts (SA). A complete absence of such precipitate in bone-related cells was also noted.In the second research term, we examined whether or not the peculiar phenomenon is specific for continuously growing teeth or is an essential one for mammalian amelogenesis. In the molar tooth germs of high-Ca perfused young rats, we observed similar mineral deposits in the ameloblast layr as those in the incisors. The inhibition of two types of Ca-binding proteins having been assumed to be related to cellular Ca-transport, and known to be contained in the cytoplasm of ameloblasts, did not make any changes in mineral deposits in the ameloblast layr.The presence of putative Ca-binding sites that appear to bind with excessively high concentration of calcium entering in the cytoplasm has been shown to be a common feature of the amelogenesis at least in rat teech, implicated its relation to the yet unknown mechamism of calcium regulation by the ameloblasts.We would like to further elaborate the biological significance of peculiar mineral deposits in Ca-loaded ameloblasts in future studies.

为了阐明牙齿和牙周矿化组织形成细胞调节钙的机制，我们的研究小组提出了一种新的方法，通过血管灌注高含钙溶液，然后进行无水组织处理，光镜和电子显微镜以及x射线微量分析，揭示细胞层中可能的钙结合位点。通过这种方法，我们发现磷酸钙颗粒沉淀只发生在基质形成阶段的成釉细胞和光滑成熟成釉细胞（SA）中。在骨相关细胞中也完全没有这种沉淀物。在第二个研究阶段，我们研究了这种特殊现象是持续生长的牙齿所特有的，还是哺乳动物变异性发生所必需的。在高钙灌注幼鼠的磨牙胚中，我们观察到成釉细胞层中的矿物质沉积与门牙中的相似。两种钙结合蛋白的抑制被认为与细胞钙运输有关，并且已知存在于成釉细胞的细胞质中，但对成釉细胞层的矿物沉积没有任何改变。假设的钙结合位点的存在似乎与进入细胞质的高浓度钙结合，至少在大鼠中已被证明是成釉细胞发生的共同特征，暗示其与尚不清楚的成釉细胞钙调节机制有关。我们希望在未来的研究中进一步阐述载钙成釉细胞中特殊矿床的生物学意义。