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

为了阐明牙齿和牙周矿化组织形成细胞调节钙的机制，我们的研究小组引入了一种新的方法，通过血管灌注动物高钙溶液，然后进行无水组织处理，进行光镜和电子显微镜和X射线显微分析，以揭示细胞层中可能的钙结合位点。用这种方法，我们发现颗粒状的磷酸钙沉淀物只发生在成釉细胞在基质形成阶段，和平滑结束的成熟成釉细胞（SA）。在第二个研究阶段，我们研究了这种特殊现象是否是持续生长的牙齿所特有的，或者是哺乳动物釉质形成所必需的。在高钙灌注年轻大鼠的磨牙牙胚中，我们观察到成釉细胞层中的矿物沉积与切牙中的矿物沉积相似。两种钙结合蛋白的抑制作用被认为与细胞内钙转运有关，并且已知其存在于成釉细胞的细胞质中，没有使成釉细胞层中的矿物质沉积发生任何变化。似乎与进入细胞质中的过高浓度的钙结合的结合位点已被证明是釉质形成的共同特征，结论：成釉细胞内钙离子浓度的变化与成釉细胞钙离子调节机制有关，因此，我们希望在今后的研究中进一步阐明成釉细胞内钙离子沉积的生物学意义。

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.