【作者】 王思聪；

【导师】 林崇韬；

【作者基本信息】 吉林大学 ， 口腔临床医学， 2007， 硕士

【摘要】 牙周病的治疗目的是去除病因,消除炎症,恢复软组织及骨的生理外形,恢复功能保持长久的疗效并且促进牙周组织再生。根据组织工程学原理,牙周组织再生的三个要素是种子细胞、生长因子和支架材料。研究结果显示,在牙周组织伤口愈合的4种来源细胞中,只有牙周膜细胞具有牙周组织再生的能力。碱性成纤维细胞生长因子具有多种生物学作用,是有丝分裂促进因子,有很好的发展潜能。核心蛋白多糖与胶原合成关系密切。因此本研究应用碱性成纤维细胞生长因子刺激体外培养的人正常牙周膜细胞,用逆转录-聚合酶链式反应检测牙周膜细胞内核心蛋白多糖的基因表达的变化来探讨碱性成纤维细胞生长因子抑制Ⅰ型胶原的机制,进一步探讨碱性成纤维细胞生长因子在牙周组织损伤修复和再生中的作用,为牙周组织再生奠定部分理论基础。更多还原

【Abstract】 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, acidic or basic fibroblast growth factor existed in bone matrix, and can stimulate DNA synthesis and cell reproduction. Decorin is one of small leucine-rich proteoglycans. Core protein of decorin consists of shorter original peptide sequence (14 amino acids). human decorin gene is on chromosome 12q23 region. It is widely distributed in the extracellular matrix, such as bone, cartilage, tendon, skin and gingiva. Decorin has a close relationship with collagen I mediated by core protein. Decorin has no bone distribution, suggesting that the role of decorin in the mineralization process. We studied the effect of bFGF on gene expression in cultured human periodontal ligament cells to further explore the role of decorin in inhibition of bFGF on type I collagen.In this study, normal human periodontal ligament cells were cultured, and exogenous bFGF was used to stimulate cells. Reverse transcription - polymerase chain reaction was used to assay decorin gene expression in cells. The suppression effect depends on the concentration of bFGF.Decorin belongs to leucine-rich proteoglycans. SLRP is sub-category belongs to small protein extracellular proteoglycans. It can be bonded to other matrix elements, assisted in the formation of collagens or excuted bridge functions between the different molecular compositions. The mature form of decotin (100 kDa) consists of an 45-kDa core protein, a single dermatan or chondroitin sulfate glycosaminoglycan chain, cysteine loops near the N and C terminus,and either two or three asparagine-bound oligosaccharides. The central part of the core protein consists of 10 leucine-rich repeat (LRR) sequences in tandem array. Rotary shadowing-electron microscopy and molecular modeling studies suggest that the DCN core protein is horseshoe-shaped and that the inner concavity accommodates and may provide a binding site for type I collagen. Some findings show that decorin may be a bridging molecule between type I and type VI collagen networks in vitro and may be also in vivo. SLRP-collagen interactions may be critical in a number of biological processes, such as maintenance and assembly of the collagenous scaffold of the extracellular matrix during growth, development and wound healing.Decorin, at densities as low as 6×10-22 mol/μm2 of decorin on bead surfaces, can inhibit internalization of collagen. One of the more intriguing activities recently ascribed to decorin is as a regulator of cell proliferation. Decorin levels are elevated during quiescence , and decorin expression is low in actively proliferating or transformed cells ,observations consistent with a role in growth inhibition. The role of decorin as an antiproliferative agent may be important in different disease states.The role of decorin in the process of tooth mineralization is not very clear. However, it’s glycosaminoglycan structure can combine calcium and interact with hydroxyapatite, and it also appeared in the pre-mineralized tissues such as bone and predentin.bFGF has a variety of biological functions. It inhibit type I collagen synthesis in periodontal ligament cells and suggests that the inhibition effect of bFGF on decorin may be one of modulate mechanisms of decreased type I collagen synthesis in PDLCs. The inhibition effect of bFGF on decorin are likely to be involved in the changes in the extracelluar matrix environment, it may play a important role in the healing process of periodontitis. In dental and periodontal tissues, the small proteoglycans express in non-mineralized dentin and cementum, collagen fibers particularly in the borderline between soft tissues and hard tissues and osteoblasts in the inner line of alveolar bone showed strong positive staining characteristics, suggesting that the small proteoglycans may affect the mineralization process of dentin, cementum and alveolar bone. bFGF may play important roles in wound healing by promoting angiogenesis and inducing the growth of immature PDLCs, and may in turn accelerate periodontal regeneration. Whether the inhibitory effect of bFGF on decorin is involved in this process is still unclear. It may participate in the process of PDL cells into mineralized formation cells. Decorin regulates cell proliferation, decorin levels are elevated during quiescence , and decorin expression is low in actively proliferating or transformed cells. bFGF can promote the proliferation of periodontal ligament cells. The inhibition effect of bFGF on decorin may be involved in it.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 decorin gene expression in periodontal ligament cells and it could provide a theoretical basis for periodontal regeneration.更多还原