干细胞靶向多肽修饰的梯度矿化的透明质酸/聚膦腈同轴电纺丝纳米纤维支架原位诱导关节骨软骨组织的再生及其修复机制的研究

There is no blood vessel in the articular cartilage and can not be repaired by itself. The repair of massive osteochondral damage has been a difficult problem in the field of sports medicine research and clinical treatment. In the previous experiments, our research successfully screened E7 (EPLQLKM) highly compatible with bone marrow stem cells (BMSCs) and proved that E7 could efficiently and specifically collect BMSCs. Therefore, we put forward the following hypothesis: Using E7 modified gradient mineralized hyaluronic acid / Polyphosphazen coaxial electrospinning nanofiber scaffold to repair giant osteochondral injury of joints. E7 is efficient and accurate to raise the endogenous BMSCs to the defect area; hyaluronic acid / polyphosphazen provides the extracellular matrix of cartilage and bone; nano electrospinning technique to simulate the three-dimensional structure of cartilage and subchondral bone; calcium phosphate salt gradient mineralization provides mechanical support for the early defect. We will verify the hypothesis by in vivo and in vitro experiments, but also in cells, tissues and animal levels to further explore the E7 target protein in stem cell membrane and its mechanism; and the mechanism of interaction between BMSCs and chondrocytes. The success of this experiment will provide theoretical and experimental basis for the clinical treatment of large articular cartilage defects, and lay a foundation for clinical application.

关节软骨没有血管，无法自身修复。巨大骨软骨损伤的修复一直是运动医学领域研究与临床治疗的棘手问题。本课题组在前期试验中成功筛选出骨髓干细胞（BMSCs）高度亲和性的靶向多肽（E7，EPLQLKM），并证明E7可高效、特异性募集BMSCs。因此我们提出如下假说：采用E7修饰的梯度矿化的透明质酸/聚膦腈同轴电纺丝纳米纤维支架修复关节巨大骨软骨损伤。E7高效、精确地募集内源性BMSCs至缺损区域；透明质酸/聚膦腈提供了骨和软骨的细胞外基质成分；纳米电纺丝技术模拟了软骨和软骨下骨的三维立体结构；钙磷盐梯度矿化为缺损处提供早期力学支撑；本研究拟通过体内和体外实验初步验证该假说；并在细胞、组织和动物水平深入探讨E7在干细胞膜表面的靶蛋白及其作用机制；以及BMSCs与软骨细胞的相互作用机制。此项实验的成功，将为临床治疗巨大关节软骨缺损，提供理论和实验依据，奠定临床应用基础。.

关节软骨没有血管，无法自身修复。巨大骨软骨损伤的修复一直是运动医学领域研究与临床治疗的棘手问题。结合本课题组筛选出的骨髓干细胞（BMSCs）高度亲和性的靶向多肽（E7，EPLQLKM）。将其用于梯度矿化的透明质酸/聚膦腈同轴电纺丝纳米纤维支架的修饰，以实现关节巨大骨软骨损伤修复。通过气凝胶凝聚、模拟体液浸润矿化、多种材料光交联实现了E7修饰的三层梯度矿化的透明质酸/聚膦聚膦腈同轴电纺丝纳米纤维支架，并且在新西兰兔的骨软骨缺损模型中进行了效果验证，对比6周、12周两个时间点的梯度修饰组、梯度组以及单相组（仅使用一种矿化程度的同种单相材料）的治疗效果，病理学结果、组织学评分和影像学检测均证明梯度修饰组的能力明显优于其余两组。三层梯度矿化拼接的修复材料的不同层次干细胞拥有不同向的分化能力，对于骨软骨缺损可以实现两相分化的效果，并且梯度修复组II型胶原的取向更接近于天然组织的分布。骨软骨缺损是目前临床骨关节炎患者的一大病因，但骨软骨缺损仍缺乏公认的修补材料并且多数不能大规模应用。本研究的临床应用可缓解患者痛苦，减少中老年患者后期的护理成本，同时迎合市场空缺，产生经济效益。