利用携载GDF-5质粒的三元酸度敏感缓释系统修复关节软骨缺损的实验研究

Cartilage defect caused by articular cartilage degeneration is a common disease. It is the major cause of motor dysfunction among old people, which could be repaired through transplantation surgery. However, the transplantation is easy to lead to secondary trauma, cell source, transplant rejection, scaffold biocompatibility and other problems. Therefore, we try to improve the repair of cartilage itself through gene therapy which could transfect cartilage cell and express some growth factors. In this research,nanoparticles loading GDF-5 plasmid will be prepared by chitosan and extracellular matrix hyaluronic acid, chondroitin sulfate, which will be used to repair cartilage defects.GDF-5 plasmid will be transformed into cartilage cells by pH-sensitive gene vetor chitosan and express GDF-5 sostenuto and highly, which could promote cartilage repair. Extracellular matrix hyaluronic acid and chondroitin sulfate could supress inflammation, relieve pain and improve motor function of the joint. The two biomaterials could repair cartilage defects without causing cytotoxicity as other gene carriers. The employment of this strategy for the repair of joint cartilage defect is an advanced approach for treating this disease cost-effectively.

关节软骨退行性变引起的软骨损伤是一种常见病、多发病，是导致中老年人运动功能障碍的最主要原因。目前软骨的移植修复通常都需要手术，容易给患者造成二次创伤，并且存在细胞来源、排异反应、支架相容性等诸多限制。因此，我们希望通过基因治疗，导入能表达促进软骨修复的生长因子的基因片段，促进软骨的自身修复。本研究拟将壳聚糖与细胞外基质透明质酸、硫酸软骨素混合，制备携载生长因子GDF-5的纳米微球，用于软骨缺损的治疗。其中壳聚糖是一种酸度敏感的基因载体材料，可以将GDF-5质粒导入到细胞内，使细胞持续的高表达GDF-5，促进关节软骨的自我修复；透明质酸、硫酸软骨素作为软骨细胞外基质，可以起到抗炎，缓解疼痛，改善关节运动的作用，不仅不具有一般基因载体材料的细胞毒性，反而可以对缺损的关节软骨起到治疗效果。本研究对关节软骨缺损的治疗具有潜在的和不可估量的社会影响和经济价值。

关节软骨退行性变引起的软骨损伤是一种常见病、多发病，是导致中老年人运动功能障碍的最主要原因。本研究希望通过制备一种新型的非病毒基因载体，携载能促进软骨生长的GDF-5质粒，探索一种关节软骨损伤的基因治疗新方法。总的来说，本研究成功的利用静电吸附的原理，将壳聚糖与细胞外基质透明质酸、硫酸软骨素混合，制备出携载生长因子GDF-5的纳米微球。扫描电镜、粒度分析、凝胶电泳的结果表明该微球粒径较为均匀，球形良好，能够成功的包裹GDF-5质粒。微球干燥粉末的红外光谱结果表明该微球由壳聚糖、透明质酸、硫酸软骨素三种成分组成。通过微球中质粒在不同pH缓冲液中的释放实验和红细胞膜的破坏试验表明，微球具有一定的酸度敏感性。体外的细胞毒性试验表明，微球细胞毒性较小，具有良好的生物相容性。同时该携载GDF-5质粒的微球在体外能够成功的转染软骨细胞，促进软骨细胞外基质的分泌；在体内，能够有效的缓解骨性关节炎所导致的关节软骨损伤。本研究的实验结果较好的完成预期的研究目标，该研究的完成对关节软骨缺损的治疗具有潜在的和不可估量的社会影响和经济价值。