SP自组装类胶原多肽基质复合磷酸钙材料用于颌骨再生的研究

The signals of nervous system play important roles in bone healing and bone remodeling, but this mechanism has not yet received attentions or been succeeded in bone tissue engineering techniques. According to the latest features of the neurotransmitter Substance P(SP), we propose a hypothesis: the SP combined with calcium phosphate could form multi-bioactivities, including stem cell mobilization and differentiation, angiogenesis promotion, and new bone induction and conduction. This project intends to synthesis the SP active collagen mimetic peptides and trigger the self-assembling of the peptides in alginate. The alginate hydrogel has good plasticity and the innner three-dimensional peptides nanofibers have good bioactivity. The compound hydrogel matrix and self-set calcium phosphate cement will be used to build novel scaffold with characteristics of easy shaping and automatic setting. Meanwhile, the hydrogel martix inside the scaffold can form high porosity and internal mesh channels. The relationships between the scaffold structure and mechanic characters will be investigated. The effect of SP on the scaffold's bioactivity will be studied in vitro utilizing hUCMSCs and hBMMSCs, including the cell proliferation, cell differentiation, cell migration, and cell secretion on the scaffolds. Also the capacity of SP scaffolds in protection of MSCs from the damage of irradiation will be observed. Rabbit model of mandibular critical defect and ectopic bone formation will be constructed for in vivo study of the composite scaffolds. The mobilization of endogenous \exogenous stem cells, promotion of angiogenesis, establishment of internal-external circulation, induction and conduction of new bone will be observed. The final objects of the study are to construct novel scaffold suitable for functional and individual reconstruction of maxillofacial bone defects, and illuminate the mechanism of SP activity on material transformation and bone regeneration.

神经支配对骨愈合、骨改建有重要作用，但神经信号调控机制对骨组织工程的意义尚未得到重视和充分利用。根据神经递质SP的最新功能发现，我们提出假说：SP结合磷酸钙可以发挥干细胞动员、血管新生刺激、和骨再生引导诱导等多向生物活性。项目拟合成SP活性类胶原多肽，在Alginate凝胶中自组装形成活性三维纳米纤维，并获得可塑性复合凝胶基质，结合CPC等无机成分，构建能随意塑形和自动固化负载、并具有高孔隙率和内部网状通道的新型生物活性支架，研究材料结构控制、力学特征；利用hUCMSCs和hBMMSCs体外研究复合材料对干细胞增殖、分化、迁移、分泌、放射线反应等活动的影响及其机制；采用兔颌骨缺损和异位成骨模型，研究复合材料对内\外源性干细胞动员分化、血管新生和内外部循环建立、引导和诱导骨再生的作用及其机制。最终形成适于颌面骨缺损个体化功能化重建的新型生物活性材料，并阐明SP对材料转化和新骨再生的作用及机制

牙槽骨、颌骨外形复杂，结构特殊，因炎症、外伤、肿瘤等导致缺损可严重影响口腔面部功能及美观，传统骨移植修复供区少、难度大并且效果不理想，具有生物诱导活性的骨替代材料研究已成为重要的探索方向。本研究基于近期在神经支配对骨愈合、骨改建重要影响的科学发现基础上，利用小分子神经递质多肽P物质（SP）干细胞动员、血管新生刺激、间充质细胞诱导成骨分化等能力，仿生模拟自然骨组织成分和结构，人工构建模块化、可塑形、能负载的适于颌面骨缺损个体化功能化重建的新型生物活性材料，并初步阐明SP促进材料转化和新骨再生的必要条件及机制。研究主要探索了无机骨引导材料自固化磷酸钙（calcium phosphate cement, CPC）、有机骨引导诱导材料胶原或类胶原自组装多肽加载SP的有效方法、复合材料构建模式、材料的体内外力学和生物学性能及转化，研究表明SP相对于大分子生长因子在活性保存、加载方式、合成便利性等方面具有显著优势，SP的加载浓度、缓释能力是影响其诱导成骨活性的重要因素，SP复合材料的成分配比、构建模式、以及内部孔隙率和孔隙结构对SP的缓释有显著影响作用，阐明可以在体内快速转化为骨组织的复合材料构建方法；研究还比较了SP物质对骨髓间充质细胞、脐带间充质细胞等的成骨诱导分化作用，证实SP诱导干细胞分化的浓度依赖性，发现脐带间充质细胞体外成骨诱导分化的新方法，提出SP用于体外自组装多肽凝胶立体培养间充质细胞，获得具有骨诱导活性的人工合成基质材料，并用于复合骨替代材料的构建；研究初步进行了新型仿生复合材料应用于异位成骨、和即刻种植的可行性研究，探索复杂牙槽骨颌骨缺损情况下进行功能性修复的新方法，获得了了较好的实验结果。研究显示SP加载自固化磷酸钙材料并复合天然胶原或人工合成类胶原构建的生物材料具有容易获得、成本较低、安全性好、活性确实、能够负载、适用广泛等优势，具有用于颌骨再生修复临床转化的较好价值。