一靶多效壳聚糖温敏水凝胶复合支架促牙槽骨内源性再生修复机制研究

The regeneration of alveolar bone is one of the basis and difficulties of periodontal tissue engineering and the clinic transformation of stem cell faced serious challenges. Endogenous regeneration of alveolar bone is very important for clinical purpose. In this study, a chitosan based thermosensitive hydrogel compound repair system was prepared. Quaternary chitosan nanoparticles (HTCCn) loaded with bone morphogenetic protein-2 plasmid DNA (pDNA-BMP2) were participated into this system （CS/HTCCn（pDNA-BMP2）-GP）. We designed experiments to improve DNA release kinetics and gene transfection efficiency to periodontal ligament cells (PDLCs). Also, studies were designed to detect improve the periodontal inflammatory microenvironment and its effect on biological properties of PDLCs. We attempted to expound the regulation mechanism of BMP/Runx2 (Runt related transduction factor2) signal tranduction pathway in process of the alveolar bone regeneration. Beagle dog perioodontitis models were set up in order to evaluate the alveolar bone regeneration effect. In this study, this thermosensitive compound sysytem inhibits “multi-effect” for alveolar bone regeneration—minimally invasive injectable \ intelligent induced alveolar bone regeneration \ anti periodontal pathogens and improving the microenvironment of periodontal inflammation. It is combined not only tissue regeneration scaffold, genetic target therapy but also local bionic sustained releasing. It is expected to play different positive effects on different bone regeneration process and mechanism with collaborative, complementary and cascade amplification effects and providing a new approach for alveolar bone regeneration.

牙槽骨的再生是牙周组织工程的基础和难点之一，干细胞的临床转化面临严峻挑战，实现牙槽骨的内源性再生具有重要的临床意义。本项目拟制备壳聚糖温敏水凝胶负载含有骨形态发生蛋白2质粒DNA (pDNA-BMP2)的壳聚糖季铵盐纳米粒（HTCCn），构建CS/HTCCn（pDNA-BMP2）-GP复方修复体系。优化体系配比及制备条件，使其具备适当的强度和降解速率，可控的相变速率；提高DNA缓释性能及对牙周膜成纤维细胞的基因转染效率；研究其对牙周炎症微环境的改变及对细胞生物学性能的影响；探讨BMP2/Runx2信号转导通路的调控机制；通过注射至牙周病动物模型，检测成骨效能。具有可微创注射\智能牙槽骨再生诱导\抑菌和改善牙周炎症微环境等“一靶多效”的作用效果，将组织工程支架、基因靶向治疗和局部仿生控释有机结合，在牙槽骨再生修复的不同环节和作用机制上发挥协同、互补和级联放大效应，为牙槽骨的再生提供新途径。

牙槽骨的再生是牙周组织工程的基础和难点之一，干细胞的临床转化面临严峻挑战，实现牙槽骨的内源性再生具有重要的临床意义。本项目通过制备壳聚糖温敏水凝胶负载含有骨形态发生蛋白2质粒DNA(pDNA-BMP2)的壳聚糖季铵盐纳米粒（HTCCn），构建CS/HTCCn（pDNA-BMP2）-GP复方修复体系。优化体系配比及制备条件；提高DNA缓释性能及对牙周膜成纤维细胞的基因转染效率；研究其对牙周炎症微环境的改变及对细胞生物学性能的影响；探讨BMP2/Runx2信号转导通路的调控机制；通过注射至牙周病动物模型，检测成骨效能。本项目研究发现，CS/CSn-GP复合修复体系具有良好的组织相容性及温敏性，是一种良好的组织工程支架。CS/CSn-GP复合修复体系有利于牙槽骨再生，包载pDNA-BMP2后促牙槽骨再生作用更为显著。CSn具有良好的形态，合适的粒径大小，可以有效地结合pDNA-BMP2，具有高的包封率和载药率。CS/CSn(pDNA-BMP2)-GP复合体系具有温敏特性及网络交联结构，可以负载CSn(pDNA-BMP2)，具有良好的缓释性能。CS/CSn(pDNA-BMP2)-GP复合体系能够保持pDNA-BMP2的结构稳定性，为其以后的功能性奠定基础。本项目通过研究具有可微创注射\智能牙槽骨再生诱导\抑菌和改善牙周炎症微环境等“一靶多效”的作用效果，将组织工程支架、基因靶向治疗和局部仿生控释有机结合，在牙槽骨再生修复的不同环节和作用机制上发挥协同、互补和级联放大效应，为牙槽骨的再生提供新途径。