Shimonishi M, Hatakeyama J, Sasano Y, Takahashi N, Komatsu M, Kikuchi M
Division of Comprehensive Dentistry, Tohoku University Dental Hospital, Sendai, Japan.
J Periodontal Res. 2008 Feb;43(1):64-75. doi: 10.1111/j.1600-0765.2007.00995.x.
Epithelial-mesenchymal interactions are responsible for cell differentiation during periodontal regeneration. The present study was undertaken to examine the expression of alkaline phosphatase and noncollagenous bone proteins, such as osteopontin, osteocalcin and bone sialoprotein, with respect to interaction between the cells of the epithelial rests of Malassez and fibroblasts from human periodontal ligament.
Explants of human periodontal ligament tissues produced outgrowths containing both putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts in a modified serum-free medium. Putative epithelial rests of Malassez cells cultured alone, and human periodontal ligament fibroblasts cultured alone, were used as controls. The expression levels of amelogenin were analyzed by in situ hybridization. The expression and distribution of alkaline phosphatase and noncollagenous bone proteins in both cell populations at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts were analyzed by immunohistochemistry, in situ hybridization and reverse transcription-polymerase chain reaction.
Amelogenin mRNA was detected at high levels only in putative epithelial rests of Malassez cells at the interface. Alkaline phosphatase and bone sialoprotein mRNAs were detected significantly at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblast cells. In particular, bone sialoprotein and its mRNA were expressed significantly in human periodontal ligament fibroblasts at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblast cells. The expressions of osteopontin and its mRNA were not different between putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts at the interface. Osteocalcin and its mRNA were expressed strongly in putative epithelial rests of Malassez cells at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts.
These findings indicate that the epithelial-mesenchymal interaction modulates the expression of alkaline phosphatase, osteocalcin and bone sialoprotein in putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts, suggesting that epithelial-mesenchymal interactions play a role in the maintenance of periodontal ligament.
上皮-间充质相互作用在牙周组织再生过程中负责细胞分化。本研究旨在探讨碱性磷酸酶以及骨桥蛋白、骨钙素和骨涎蛋白等非胶原蛋白在马拉瑟上皮剩余细胞与人类牙周膜成纤维细胞相互作用方面的表达情况。
在改良的无血清培养基中，人牙周膜组织外植体生长出含有假定的马拉瑟上皮剩余细胞和人牙周膜成纤维细胞的细胞群。单独培养的假定马拉瑟上皮剩余细胞和单独培养的人牙周膜成纤维细胞用作对照。通过原位杂交分析釉原蛋白的表达水平。通过免疫组织化学、原位杂交和逆转录-聚合酶链反应分析假定的马拉瑟上皮剩余细胞与人牙周膜成纤维细胞界面处两种细胞群体中碱性磷酸酶和非胶原蛋白的表达及分布。
仅在界面处的假定马拉瑟上皮剩余细胞中高水平检测到釉原蛋白mRNA。在假定的马拉瑟上皮剩余细胞与人牙周膜成纤维细胞界面处显著检测到碱性磷酸酶和骨涎蛋白mRNA。特别是，在假定的马拉瑟上皮剩余细胞与人牙周膜成纤维细胞界面处的人牙周膜成纤维细胞中显著表达骨涎蛋白及其mRNA。界面处假定的马拉瑟上皮剩余细胞与人牙周膜成纤维细胞之间骨桥蛋白及其mRNA的表达无差异。在假定的马拉瑟上皮剩余细胞与人牙周膜成纤维细胞界面处的假定马拉瑟上皮剩余细胞中强烈表达骨钙素及其mRNA。
这些发现表明上皮-间充质相互作用调节假定的马拉瑟上皮剩余细胞和人牙周膜成纤维细胞中碱性磷酸酶、骨钙素和骨涎蛋白的表达，提示上皮-间充质相互作用在维持牙周膜中起作用。
