An effect of FGF on periodontal ligament-derived epithelial cell proliferation and differentiation for a regenerative dental implant therapy

人牙周韧带衍生的上皮细胞（Malassez上皮剩余物：ME）来源于Hertwig上皮根鞘。本研究建立了人牙周膜成纤维细胞无血清培养体系，采用无血清生长实验研究了成纤维细胞生长因子（FGF）对人牙周膜成纤维细胞（PLF）的促有丝分裂作用。此外，我们还通过逆转录-聚合酶链反应（RT-PCR）、PCR-Southern杂交、免疫组化、蛋白质印迹和核糖核酸酶保护试验（RPA）等方法，证实了FGF受体（FGFR）在ME中的表达和FGF在PLF中的表达。FGF-1和FGF-7/角质形成细胞生长因子（KGF）均刺激ME的细胞生长，而FGF-1和FGF-2均刺激PLF的细胞生长。RT-PCR和PCR-Southern分析显示ME表达FGFR 2-（IIIb）mRNA，但不表达FGFR 1-（IIIc）、FGFR 2-（IIIc）、FGFR 3-（IIIb）、FGFR 3-（IIIc）和FGFR 4的mRNA。FGF-7/KGF的免疫组化分析显示，免疫反应性FGF-7/KGF主要在哪种类型的细胞的细胞质中检测到。PCR-Southern、Western blotting和RPA检测结果显示，PLF表达FGF-7/KGF mRNA。这些结果表明，FGF-FGFR 2-（IIIb）系统在ME的生长和分化中起着重要作用。此外，内源性产生的FGF作为旁分泌的相互作用调节ME和PLF之间的生长和分化。

Human periodontal ligament-derived epithelial cells (Epithelial rests of Malassez : ME) are derived from Hertwig's epithelial root sheath. In this study, we have developed a serum-free culture system of ME. The mitogenic effect of fibroblast growth factor (FGF) in the ME, human periodontal ligament-derived fibroblast cells (PLF) were investigated by serum-free growth assay. In addition, we demonstrated the expression of FGF receptor (FGFR) in the ME and the expression of FGF in the PLF by reverse transcription-polymerase chain reaction (RT-PCR), PCR-Southern hybridization, immunohistochemical examination, western blotting and ribonuclease protection assay (RPA). Both FGF-1 and FGF-7/keratinocyte growth factor (KGF) stimulated cell growth of the ME. On the other hand, both FGF-1 and FGF-2 stimulated cell growth of the PLF. RT-PCR and PCR-Southern analysis revealed that the ME expressed FGFR2-(IIIb) mRNA but not mRNAs for FGFR1-(IIIc), FGFR2-(IIIc), FGFR3-(IIIb), FGFR3-(IIIc) and FGFR4. An immunohistochemical analysis of FGF-7/KGF revealed that immunoreactive FGF-7/KGF were detected predominantly in the cytoplasm of which type of cell. PCR-Southern, western blotting and RPA revealed that the PLF expressed FGF-7/KGF mRNA. These results suggest that the FGF-FGFR2-(IIIb) system play an important role in the growth and differentiation of ME. In addition, endogenously produced FGFs work as paracrine interactive regulators of the growth and differentiation between ME and PLF.