神经源性细胞外基质支架复合间质细胞衍生因子-1促进周围神经缺损修复及机制研究

The artificial nerve graft is an effective measure to repair the nerve defect, but its effect of repair is still not ideal. Recent studies have shown that stromal cell-derived factor -1 (SDF-1) has a function to promote stem cell homing. It has not been determined that whether nerve scaffold composite SDF-1 raise homing of bone marrow mesenchymal stem cells (BMSCs) to promote nerve defect repair or not. In our previous study, nerve-derived extracellular matrix (ECM) was prepared and found adding BMSCs around nerve defects to promote nerve repair, and we plan to manufacture a nerve-derived ECM scaffold of increased stem cell homing. This study intends to construct a new kind of nerve scaffold which promotes stem cell homing and improves nerve regeneration. First of all, electrospinning technology is used to prepare sustained release of SDF-1 nanofiber film and study the release kinetics of SDF-1. Second, Transwell and stem cell tracer methods are employed to study raising the BMSCs of nanofiber film in vivo and in vitro. Orientation ECM scaffold is prepared by directional crystallization and then complex nanofiber film to build the core-shell structure biomimetic scaffold, of which structure, mechanical properties and biological activity are evaluated. Finally, its effect of repair sciatic nerve defect is evaluated by functional recovery and histological method, and distribution and outcome of recruitment cell was investigated by stem cell tracer techniques. The research will provide new ideas and theory basis for the development of nerve tissue engineering.

目前人工神经移植物是修复神经缺损的有效措施，但其修复效果仍不理想。最新研究表明，基质细胞衍生因子-1（SDF-1）具有促进干细胞归巢的作用，而神经支架复合SDF-1能否募集骨髓间充质干细胞（BMSCs）促进神经缺损修复尚未确定。本项目在前期制备神经源性细胞外基质（ECM）和发现神经缺损周围添加BMSCs促进神经修复的基础上，拟构建具有促干细胞归巢的ECM来源新型支架。本研究拟采用电纺丝技术制备缓释SDF-1的纳米纤维薄膜，研究SDF-1的释放动力学并利用Transwell、干细胞示踪等方法明确其体内外、募集BMSCs；然后将其同定向结晶技术制备的取向性ECM支架复合，构建 "壳-芯"结构仿生支架，评价其结构、力学性能和生物活性；最后通过功能恢复和组织学评价修复大鼠坐骨神经缺损效果，并运用干细胞示踪技术探讨募集细胞的分布及转归。该研究的开展将为组织工程神经的研制提供新思路和理论基础。

周围神经缺损的修复与重建是当前神经损伤治疗领域的一大难题, 现有周围神经支架材料修复效果仍不理想。研发能够有效代替自体神经的移植替代物，对提高临床神经损伤修复效果起到积极的推动作用，具有重要的社会价值和明显的市场应用前景。组织工程的发展为提高周围神经损伤修复效果带来希望。本项目在前期制备神经源性细胞外基质（ECM）和发现神经缺损周围添加BMSCs促进神经修复的基础上，围绕构建促干细胞归巢的新型组织工程神经开展探索性的工作。首先采用电纺丝技术制备缓释基质细胞衍生因子-1（SDF-1）的纳米纤维薄膜，然后将其同定向结晶技术制备的取向性ECM支架复合，构建了缓释SDF-1的PPC-ECM支架，通过体外实验评价其结构、力学性能和生物活性，并评价其修复大鼠坐骨神经缺损功能恢复和组织学指标应用效果。项目按研究计划实施完成，研究结果显示该支架具有“壳-芯”结构、生物力学仿生和良好生物相容性，建立与背根神经节共培养技术，在体外实验中证实缓释SDF-1的PPC-ECM 仿生支架具有趋化BMSCs的作用，并在动物实验发现其具有促进周围神经损伤修复的作用，其作用机制与早期募集干细胞归巢相关。本项目研制的促干细胞归巢的ECM来源结构仿生支架，有助于为下一步组织工程神经的研制提供新思路和技术参考。