骨缺损修复需要成骨相关因子和支架材料。microRNA-26a（miR-26a）是调控成骨成血管分化的重要因子。尿源干细胞来源外泌体（ exosome derived from urine stem cells ，USCs-Exo）是理想的miRNA转运系统。稀土镧元素掺杂支架具有促进骨再生的作用。在早期研究基础上，本项目探索负载miR-26a的USCs-Exo复合含镧元素支架修复骨缺损的潜能。首先利用电转染将miR-26a导入USCs-Exo，研究大鼠骨髓间充质干细胞（BMSCs）与负载miR-26a的USCs-Exo相互作用。然后利用冷冻干燥和原位转化复合技术制备镁镧类水滑石/壳聚糖三维多孔支架。最后将负载miR-26a的USCs-Exo复合镁镧类水滑石/壳聚糖支架植入骨缺损处，检测体内骨修复作用。本项目的实施将为骨缺损修复提供了新的方法。

Repair of bone defects need osteogenic factors and scaffold. MicroRNA-26a (miR-26a) is key factor that regulate osteogenic and angiogenic differentiaiton. Exosome derived from urine stem cells (USCs-Exo) is ideal miRNA transport system. Rare earth lanthanum dopped scaffold can promote bone regeneration. On the basis of the previous studies, this project will explore the potential of USCs-Exo load miR-26a in combination with lanthanum dopped scaffold to repair bone defects. MiR-26a is transfected into USCs-Exo by electroporation, and the interaction between miR-26a loaded USCs-Exo with rat bone marrow mesenchymal stem cells (BMSCs) is studied. Then, magnesium lanthanum hydrotalcite/chitosan 3D porous scaffolds are prepared by freeze drying and in-situ transformation. Finally, USCs-Exo load miR-26a in combination with magnesium lanthanum hydrotalcite/chitosan scaffold is implanted into the bone defect, and bone regeneration is detected.The implementation of this project will provide a new method for the repair of bone defects .