Mg2+调控BMSCs源外泌体运载miR-223-3p介导炎性微环境改变对成骨分化影响机制研究

对严重创伤骨折患者，尽早控制原发损伤，减少炎症的继发损伤并促进骨修复是创伤骨科医生亟待解决的问题。镁基材料及镁离子能调节炎症和促进成骨，但确切机制尚未阐明。骨髓间充质干细胞（BMSCs）可参与调节炎性微环境，是目前的研究热点。我们前期已发现镁离子上调BMSCs源外泌体中miR-223-3p表达，外泌体调节巨噬细胞NLRP3表达和极化比例，巨噬细胞极化调节成骨分化。由此提出假说：镁通过BMSCs源外泌体运载的miR-223-3p抑制巨噬细胞NLRP3炎症小体，炎症小体介导的巨噬细胞极化通过调节炎性微环境中的细胞因子促进成骨。为验证假说，本项目首先采用体外实验阐明镁离子通过BMSCs源外泌体中miR-223-3p调控巨噬细胞NLRP3炎症小体，进而明确炎症小体调控细胞因子分泌促进BMSCs成骨分化，最后采用大鼠多发骨折体内模型进行验证。为应用镁基材料救治严重创伤骨折患者提供新思路和理论依据。

For the treatments of patients with severe traumatic fractures, it is important and urgent for traumatic orthopedists to control the primary injury, reduce the secondary inflammatory injury and promote the bone repair as early as possible. Magnesium-based materials and magnesium ions can regulate inflammation and promote osteogenesis, but the exact mechanisms are still unclear. Bone marrow mesenchymal stem cells (BMSCs) can participate in the regulation of inflammatory microenvironment, it is a recent research hot topic. Pre-experiments found that magnesium ions increased the expression of miR-223-3p in the BMSCs-derived exosomes, the exosomes inhibited the expression of macrophage NLRP3 protein and regulated the macrophage polarization ratio, the polarized macrophages regulated the BMSCs osteogenic differentiation. Therefore, we hypothesize that magnesium ions can regulate the expression of miR-223-3p in BMSCs-derived exosomes, the miR-223-3p carried in the exosomes will inhibit the activation of NLRP3 inflammasomes, NLRP3 inflammasome-mediated macrophage polarization promotes BMSCs osteogenic differentiation by regulating cytokines in the microenvironment. To verify this hypothesis, we will firstly carry out in vitro experiments to prove that magnesium ions regulate the macrophage NLRP3 inflammasomes through miR-223-3p carried in BMSCs-derived exosomes, and then confirm that the macrophage NLRP3 inflammasomes regulate the macrophage cytokine secretion to promote BMSCs osteogenic differentiation, finally test the in vitro experiment results by animal experiments with rat multiple fractures model. The research results will provide new ideas and theoretical basis for the early application of magnesium-based materials in the treatment of severe traumatic fracture patients.