调控内源性干细胞（BMSCs）原位促腱-骨愈合人工韧带支架的研究

The choice of grafts in anterior cruciate ligament (ACL) reconstruction is one of the hot issues in sports medicine. Reconstruction of the anterior cruciate ligament using polyethylene terephthalate (PET) artificial ligament showed satisfactory medium-term and short-term clinical outcomes, but ligaments can cause serious side effects such as poor tendon-bone healing. Until now, the LARS artificial ligament graft has not yet reached the real "ligamentization" after ACL reconstruction surgery. Our previous studies have shown that simple nano biomimetic mineralization coating modification could improve the hydrophilicity and biocompatibility of PET artificial ligament. However, the effect of single coating to promote graft and bone healing was limited. In this study, stromal cell derived factor-1(SDF-1) and bone morphogenetic protein 7 (BMP-7) were co loaded onto polycaprolactone (PCL) nanofiber membrane through layer-by-layer self-assembly technique, and then a new type drug controlled release and high histocompatibility PCL/PET hybrid artificial ligament was fabricated. In order to induce endogenous bone marrow mesenchymal stem cells (BMSCs) mobilization, homing, proliferation and differentiation in situ and promote graft-to-bone healing after ACL reconstruction. In this study, we hope to construct a new type bionic hybrid artificial ligament which has high biomechanical intensity, good biocompatibility, simulation natural extracellular matrix structure and bioactivity. This research will provide theoretical and experimental basis for the development of a new type of artificial ligament.

膝前交叉韧带（ACL）损伤后选择何种移植物进行手术重建是运动医学研究的热点之一。临床上采用聚对苯二甲酸乙二醇酯（PET）人工韧带重建ACL中短期效果较好，但移植物与宿主骨间长期生物愈合较差，未能达到术后移植物真正“韧带化”要求。前期研究表明采用简单纳米仿生矿化涂层对PET人工韧带进行改性修饰可改善移植物亲水性和生物相容性，但单一涂层对于促进移植物与骨愈合作用有限。本课题拟采用层层自组装技术将基质细胞衍生因子1和骨形态发生蛋白7共同负载于聚己内酯（PCL）静电纺丝膜纤维上，并与PET材料复合构建新型仿生“杂化”人工韧带支架，以期在移植物骨隧道中诱导内源性BMSCs归巢、原位分化，进而促进移植物与宿主骨的愈合，并探讨其相关分子机制。本课题期望构建一种具有足够生物力学、良好生物相容性、可模拟细胞外基质三维结构、且具有生物活性的仿生人工韧带支架，为研制符合临床需求的新型人工韧带提供理论和实验依据。

膝前交叉韧带（ACL）损伤后选择何种移植物进行手术重建是运动医学研究的热点之一。临床上采用聚对苯二甲酸乙二醇酯（PET）人工韧带重建ACL中短期效果较好，但移植物与宿主骨间长期生物愈合较差，未能达到术后移植物真正“韧带化”要求。前期研究表明采用简单纳米仿生矿化涂层对PET人工韧带进行改性修饰可改善移植物亲水性和生物相容性，但单一涂层对于促进移植物与骨愈合作用有限。本课题成功采用层层自组装技术将基质细胞衍生因子1和骨形态发生蛋白7等生长因子负载于聚己内酯（PCL）静电纺丝膜纤维上，筛选出最佳自组装层数负载药物的PCL纳米纤维膜并与PET材料复合成功构建新型仿生“杂化”人工韧带支架。碱性磷酸酶及茜素红染色实验证实层层自组装负载BMP-7的PCL静电纺丝膜具有长期诱导BMSCs成骨方向分化的能力。体内实验结果表明，负载药物的杂化支架韧带具有良好的生物相容性及骨诱导性能。同时所构建的负载SDF-1与BMP-2双因子的PCL静电纺丝纳米纤维膜促进了BMSCs迁移，归巢和原位矿化，可提高自体肌腱移植物与骨隧道界面的愈合效果。研究表明，所构建的新型杂化仿生支架材料为手术重建膝关节前交叉韧带提供新的移植物选择方向。