巨噬细胞M1/M2极化在骨组织的损伤修复过程中发挥了重要作用。在颌骨骨折愈合过程中，间充质干细胞（MSC）是否参与巨噬细胞极化的调控，目前尚不清晰。外泌体是一种具有脂质双层膜结构的纳米级小囊泡，其内载有miRNAs及功能性蛋白等物质，可以在细胞之间传送并由此调节细胞活动。在前期研究的基础上，我们发现间充质干细胞来源的外泌体可以影响巨噬细胞的极化。miRNAs在介导细胞通讯中发挥了重要作用，本项目拟通过miRNAs过表达、沉默技术及分子生物学技术，明确MSC通过外泌体及其miRNAs调控巨噬细胞极化的具体分子机制；并通过构建颌骨骨折动物模型，利用同轴静电纺丝支架材料负载MSC外泌体，探讨MSC外泌体及其miRNAs调控巨噬细胞极化在颌骨骨折愈合过程中的作用，进一步完善骨折愈合过程的分子生物学机理。

Macrophage M1/M2 polarization plays an essential role in bone tissue injury and repair. However, whether mesenchymal stem cells(MSC) participate in the regulation of macrophage polarization during jaw fracture healing is still unclear. Exosomes are nano-sized vesicles with lipid bilayer membranes. The miRNAs and functional proteins-containing exosomes can be transmitted between cells and thereby regulate cell activity. On the basis of previous studies, we found that exosomes derived from MSC could affect the polarization of macrophages. miRNAs play an important role in mediating cell-cell communication. This project intends to clarify the specific mechanism of MSC-derived miRNAs-containing exosomes regulating macrophage polarization through miRNAs overexpression or silencing technology and molecular biology technology. In addition, an animal model of jaw fracture will be constructed. The MSC exosomes will be incorporated into coaxial electrostatic spinning scaffold which aims to explore the molecular mechanism of MSC-derived exosomes and containing miRNAs in regulating macrophage polarization during jaw fracture healing. And this research will further enrich the molecular biological mechanism of fracture healing process.