In vivo and in vitro study on tructure and function of dental pulp proteoglycan

在体外实验中，对PTHrP缺陷小鼠的牙髓组织进行了观察。在这些小鼠中，可以看到磨牙牙胚周围加速的牙槽骨形成，牙乳头被这些骨组织压缩。VERSICAN和透明质酸的免疫组织化学染色在面对侵袭性骨组织的区域均可见。在树脂包埋切片中，甲苯胺蓝染色的组织异色表现为牙乳头细胞之间的网状结构，这种网状结构在面对骨组织侵袭的区域变得细小。这些结果表明，就像软骨中的聚集素一样，凡西嘉和透明质酸在体内也有抵抗压力的能力。地高辛标记的cRNA探针原位杂交结果显示，与对照组(野生型)小鼠相比，PTHrP基因缺陷小鼠牙睑中的versican基因表达显著增加。这一现象也支持上述两种分子的功能。我们已经在会议上报告了这些结果，目前正在准备论文。我们还对直接盖帽后猴子牙髓中出现的巨噬细胞样细胞进行了超微结构观察。这些细胞胞浆内有许多溶酶体样颗粒，这些颗粒含有和处置牙本质尖端和盖帽材料，包括Dycal和树脂填充物。此外，淋巴管样管中也含有这些物质。这些结果表明，巨噬细胞在直接封盖后，作为一种防御机制，直接参与了封盖材料的处置。我们已经在会议上报告了这些结果，现在正在提交论文。另一方面，利用这笔资金，我们对小鼠髁突和四肢芽软骨进行了原位杂交和免疫组织化学研究，结果发表在期刊上。

In in vitro study, observations on dental pulp tissues in PTHrP-deficient mice were executed. In these mice, accelerated alveolar bone formation was seen around the molar tooth germ and dental papilla was compressed by these bone tissues. Strong immuohistochemical staining for both versican and hyaluronan was seen in regions facing to invading bone tissues. In resin embedded sections, tissue metachromasia with toluidine blue staining showed a network structure among dental papilla cells and this network structure became fine in regions facing to invading bone tissues. These results indicated that, like aggrecan in cartilage, versican and hyaluronan have an ability to resist compressive forces in vivo. In situ hybridization using digoxigenin-labeled cRNA probes indicated that versican mRNA was distinctively increased in dental palilla of PTHrP-deficient mice compared to that in control (wild-type) mice. This phenomenon also supported functions of both molecules described above. We have already reported these results in meeting and now are preparing for papers.We also made an ultrastructural observation on macrophage-like cells emerging in monkey dental pulp after direct capping. These cells had many lysosome-like granules in cytoplasm and these granules contained and disposed dentin tips and capping materials including Dycal and resin filler. Further, lymph capillary-like vessels also contained these substances in the lumen. These results indicated that macrophages are directly involved in the disposal of capping material as a sigh of defense mechanism after direct capping. We have already reported these results in meeting and now are submitting papers.On the other hand, using this grant, we executed in situ hybridization and immunohistochemical study Of mouse condylar and limb bud cartilage and results were published in journals.