The induction of periodontal tissues by dentin-derived matrix

脱矿化的牙本质基质在植入部位具有诱导异位骨形成的高潜力，这意味着牙本质基质中存在某些生物活性分子，促进局部细胞分化为软骨细胞和/或成骨细胞。本研究的目的是验证一种假设，即形成牙根本质的基质成分实际上可能有助于牙周组织的诱导，主要是在牙齿发育过程中牙周间充质细胞向成牙骨质细胞的分化。该研究的最终目标是鉴定生物活性分子，并将数据应用于牙周组织的再生。HEBP是一种双膦酸盐，已知对生物矿化具有高度抑制作用，而不会对骨骼和牙齿细胞的基质形成功能造成明显干扰。我们注意到，在受hebp影响的动物中，更多的牙髓沉积在根表面，而在生理条件下，如果形成的牙根牙本质的矿化受到抑制，那么未矿化的牙本质表面就会暴露在未来的牙周韧带中。免疫组织化学数据显示，牙本质唾液蛋白是牙本质基质的主要非胶原成分之一，它可以穿透牙本质的非矿化层并扩散到未来的牙周韧带中，这意味着当牙本质矿化受到抑制时，蛋白质分子会通过牙本质层发生动态易位。在这些地区，尽管牙本质基质中含有低分子的淀粉原蛋白，而且据报道成牙本质细胞至少通过PCR分析可以瞬间表达淀粉原蛋白信息，但免疫组织化学无法定位淀粉原蛋白。在正常的牙齿发育过程中，牙本质和牙釉质形成细胞层之间的上皮间质界面是串音的场所，各种信号分子在此交叉。我们的数据表明，非矿化的牙本质层允许各种分子在两个细胞层之间几乎自由通过，这些细胞层分别产生非胶原牙本质基质蛋白和某些淀粉原蛋白mRNA剪切产物，这可能有助于诱导成牙骨质细胞并进一步形成牙周组织。在未来的研究中引入高灵敏度的分析方法，可能会使在牙根本质表面新生形成部位诱导成牙胶细胞的候选分子的不同定位可视化。少

The demineralized dentin matrix has been known to have a high potential to induce ectopic bone formation at the site of implantation, implicating presence of certain bioactive molecules in the dentin matrix that facilitate differentiation of local cells into the chondrogenic and/or osteogenic cells. The aim of current investigation was to test a hypothesis that matrix components of the forming root dentin may in fact contribute to the induction of periodontal tissues, primarily on the differentiation of periodontal mesenchymal cells to cementoblasts, in the process of tooth development. The final goal of the study was to identify the bioactive molecule(s) and apply the data for the regeneration of periodontal tissues.HEBP is a type of bisphosphonate known to have high inhibitory effects on biological mineralization without causing notable interferences on the matrix forming functions of the cells of bones and teeth. We have noticed that, in the HEBP-affected animals, thick cellular cem … More entum is deposited on the root surface, where only acellular cernentum is known to form under physiological conditions, if mineralization of the forming root dentin is inhibited and hence the non-mineralized dentin surface is exposed to the future periodontal ligament. Immunohistochemical date revealed that dentin sialaprotein, one of major non-collagenous components of dentin matrix, penetrates through the non-mineralized layers of dentin and diffuses into the future periodontal ligament, implicating dynamic translocation of the proteinaceous molecules through dentin layers, if mineralization of dentin is inhibited. In such areas, amelogenin proteins could not be localized by immunohistochemistry, despite the fact that dentin matrix contains low molecular amelogenins and that odontoblasts are reported to transiently express amelogenin messages at least by PCR analyses.In normal tooth development, the epithelial-mesenchymal interface between the enamel and dentin forming cell layers is the site of crosstalk, where various signaling molecules are crisscrossing. Our data indicate that non-mineralized mantle dentin layers allow almost free passage of various molecules between the two cell layers that respectively generate non-collagenous dentin matrix proteins and certain amelogenin mRNA splice products, which might contribute to the induction of cementoblasts and further the formation of periodontal tissues. Introduction of highly sensitive analytical methods in future studies may allow visualization of distinct localization of candidate molecules for the induction of cementoblasts at the site of de novo formation of root dentin surface. Less