| Periodontal diseases comprise a group of infections that lead to irreversible loss of tissue support around the teeth. The ultimate goal of periodontal therapy is the regeneration of the destroyed tissues to their original structure and function. The results showed that periodontal tissue in the wound healing source of the four types of cells, only periodontal ligament cells with the capacity of periodontal tissue regeneration. PDLC phenotypic differentiation play an important role between the two sclerous tissues maintain their own stability in the periodontal tissue.In periodontal tissue regeneration process, PDLC phenotypic differentiation determines prognosis and turnover of treatment.At present studies show that PDLC is a group of heterogeneity of cells, including fibroblasts, osteoblasts, cementoblasts cells and the precursor cells of these cells.Lin when analyzes the PDLC group the heterogeneit of the PDLC group thought that the PDLC may divide into two categorys, one kind has the osteogenic phenotype cell, take alkalinity phosphatase (ALP), osteoponti (OPN) and so on as the marker; One kind has the fibrogenic phenotype cell, expresses EGFR,â…«collagen and so on is a characteristic.Periodontal ligament can maintain certain width throughout in alveolar bone and cement these two kind of Mineralized tissue, without mineralization, suggesting that there must be some mechanism to fibrogenic and osteogenic phenotype reached a dynamic equilibrium.EGFR is a single-chain transmembrane glycoprotein, when its ligand or conversion factor binding, its protein tyrosine kinase is activated, through a series of intracellular signal transduction initiated the nucleus DNA, to regulate apoptosis, proliferation, differentiation and migration of the cell and circulate of cell cycle. EGFR play key role in the growth, development, metabolism of normal tissue and the wound healing process, and in a variety of tumor types EGFR is over-expression and mutation such as abnormal activation. EGFR in a mature in PDLC is no expression or just low concentration expression. However, at some precursor cells and regeneration tissues in periodontal tissue the expression of EGFR markedly improved, and the pre-osteoblasts and pre-chondroblasts expressed a large number of EGFR, with their differentiation the expression of EGFR sharply reduced , the mature osteoblast and chondrocyte is not to express EGFR. The increase of expression of EGFR could inhibit PDLC differentiate into the direction of osteoblast, EGFR has capability to maintain fibrogenic phenotype of PDLC, the variation of EGFR response to the changes in the fibrogenic phenotype of PDLC.Basic fibroblast growth factor bFGF is a heparin bond peptide, which has a variety of biological activity in promoting cell proliferation, differentiation and adhesion. bFGF effectively promotes the periodontal ligament fibroblasts(PLFS) chemotaxis and proliferation, and can stimulate DNA synthesis and cell reproduction. bFGF can enhance the proliferation response of PDLC in dose-dependent manner, its biggest role in promoting caryocinesia in concentration is 10 ng/ml. In addition, the bFGF can inhibit ALP activity and the formation of mineralized nodules, bFGF have significant up-regulation role in laminin, but down-regulation role in the synthesis of the typeâ… collagen. bFGF also inhibit the PLAP-1 (Periodontal-ligament-associated protein-1) expression which has a positive regulatory role in the mineralization process of PDLC. bFGF may promote regeneration of the periodontium by induce pedo-mature periodontal ligament cells and inhibit periodontal ligament cells differentiate into cell formated mineralized tissue.Method: We gathered health premolars of young people aged 12-18 because of the removal of the orthodontic, washed tooth with stroke-physiological saline solution 2-3 times, cleaned blood and bacteria at surface of crown and root. We scraped the periodontal ligament in root 1/3 use of subgingival curette, then cultured in vitro with the mathod of enzyme digestion and tissue culture, human periodontal ligament cells were cultured and got cell clone by the method of limiting dilution. PDLC were stimulated by bFGF in different concentration and without bFGF as a negative control group, then gene expression of epidermal growth factor receptor was assessed by RT-PCR. Results: The mRNA expression of epidermal growth factor receptor was promoted by basic fibroblast growth factor and the effect was dose-dependent. The negative control group without bFGF express EGFR lower, with the concentration of bFGF increased EGFR expression was significantly promoted. The promotion was weakest in 0.1ng/ml, and strongest in 10ng/ml. Conclusion: bFGF maintain PDLC phenotype of fibrogenic stability, inhibit it differentiate into osteoblast, the effect may be one of important factors which participate in the healing process of periodontitis.In short, periodontal tissue regeneration is a complicated process, and the specific role of periodontal ligament cells in the periodontal tissue regeneration is not very clear. Study in roles of each growth factor in periodontal tissue regeneration and the combined effects of growth factors also need long time. We explore the mechanisms of bFGF in periodontal regeneration through studies of effect of bFGF on EGFR gene expression in periodontal ligament cells and it could provide a theoretical basis for periodontal regeneration.
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