仿生电场促钙离子内流并沿电场方向聚集影响半桥粒形成进而介导牙龈上皮-种植体结合

With the popularity of implant dentistry, peri-implant tissue inflammation has become an intractable problem in clinic. Promoting the quality of gingival epithelial - implant junction by improving the surface physical and chemical properties of the implant (chemical properties of the material surface topology, etc.) as to protect osteointegration from invasion of bacteria and inappropriate mechanical stimulation is one of the hot spot issues today. Teeth, gingival epithelium and bone tissue are found to have electrophysiological characteristics that teeth under occlusion, trauma of the gingival epithelium and bone tissue generates electric fields of 3~ 10mv, -40 ~-25mv and -90~-60mv, respectively..Previous studies have shown that influx and aggregate along the direction of electric field of calcium ions under physiological electric field could activate PI3K, Pten, MAPK and other signaling pathways, promote proliferation of gingival epithelial cells and build the cell connections. Calcium ions, can regulate the formation of hemidesmosomes directly: degradation in high concentration via CaM signaling pathway, formation with low concentration. .Base on these findings, we hypothesized that biomimetic electrophysiology implant material regulate the formation of gingival epithelial – implant junction by promoting calcium ions influx and intracellular redistribution, which regulate the formation of hemidesmosomes via CaM signaling pathway directly or PI3K, Pten and MAPK signaling pathways indirectly. This project aims at constructing ferroelectric implant materials with electric field of 75mv, 40mv, 10mv, 0mv, -10mv, -40mv, -75mv by simulating the electrophysiology of teeth, gums and bones; on which evaluate the proliferation of gingival epithelial cells and the formation of hemidesmosomes, and explore the relationship between which and the influx and redistribution of calcium ions, and the activation of CaM, PI3K, Pten, MAPK signaling pathway. Then canine mandible implantation experiment of these materials will be carried out to verify the hypothesis. Base on all of these researches, the mechanism of biomimetic electric field mediated the formation of gingival epithelial-implant junction will be elucidated, providing theoretical support for the development and application of biomimetic electrophysiological implant materials with the function of low risk of inflammation in surrounding tissues and long-term intrabony stability.

种植体周围组织炎症是临床棘手问题。通过改变种植体理化特性改善牙龈上皮-种植体间半桥粒结合，增强局部防御能力是当前研究热点。牙齿受力、牙龈及骨创伤分别产生3~10mv、-40~-25mv和-90~-60mv的电场。生理电场促使钙离子内流并沿电场方向聚集，激活CaM、PI3K、Pten、MAPK等信号通路介导牙龈上皮细胞增殖并重建细胞连接。我们提出假说：仿电生理种植材料通过调控胞内局部钙离子浓度影响半桥粒形成介导牙龈上皮-种植体结合。本项目拟仿牙齿、牙龈和骨电生理构建75mv、40mv、10mv、0mv、-10mv、-40mv、-75mv电场的铁酸铋种植材料；观察材料表面牙龈上皮细胞增殖、半桥粒形成状况，及其与钙离子内流、胞内分布及CaM、PI3K、Pten、MAPK信号通路的关系，并以犬下颌牙龈植入实验验证假说，阐明仿生电场介导牙龈上皮-种植体结合的机制，为开发仿电生理种植材料提供理论支持。

种植体周围组织炎症是临床棘手问题。通过改变种植体理化特性改善牙龈上皮-种植体间半桥粒结合，增强局部防御能力是当前研究热点。牙齿受力、牙龈及种植窝洞分别产生3~10mv、-40~-25mv和-90~-60mv的电场。生理电场促使钙离子内流并沿电场方向聚集，激活CaM、PI3K、Pten、MAPK等信号通路介导牙龈上皮细胞增殖并重建细胞连接。我们提出假说：仿电生理种植材料通过调控胞内局部钙离子浓度影响半桥粒形成介导牙龈上皮-种植体结合。本项目实施过程中构建75mv、0mv、-75mv仿生电位的铁酸铋种植材料。进一步细胞实验果显示75mv组牙龈上皮细胞半桥粒表达量显著高于-75mv组，对照组表达量最低；机制研究显示75mv组和-75mv组可以促进钙离子内流进而提高细胞内钙离子浓度；75mv组细胞内钙离子在细胞顶部聚集，-75mv组则在细胞底部聚集，对照组细胞内钙离子分布均匀。进一步研究显示75mv组细胞顶部细胞膜发生膜电位去极化；-75mv组细胞底部细胞膜发生膜电位去极化；对照组细胞膜电位未发生去极化。此外75mv组细胞CAM表达量高于其他二组。这些结果提示75mv的材料表面电势对牙龈上皮细胞半桥粒的形成具有显著促进作用，有望为新型种植体基台设计开发提供指导。