高弹性石墨烯多孔支架复合自体浓缩生长因子促进软骨再生及其机制研究

Articular cartilage defects seriously affect the quality of life. It is urgent to find the biomaterial with sustained chondrogenic ability and matched mechanical property. We known that graphene has excellent mechanical properties, adsorbability and biocompatibility, indicating its great potential for cartilage regeneration. In our preliminary experiments, we have prepared highly elastic graphene scaffolds which could simulate mechanical performances of cartilage. But how to get the sustained chondrogenic ability? The regeneration function and specific molecular mechanisms of carticular cartilage regeneration by graphene with sustained release of growths factors owing to its excellent adsorbability is not clear. This topic will be researched deeply to understand how graphene combined with autologous concentrated growth factors enhances cartilage regeneration by four studies: 1) To establish composite material and evaluate its physicochemical properties; 2) The study of the compatibility, degradability and chondrogenic ability of composite material；3) The study of composite material as an artificial cartilage substitute to repair articular cartilage defect of rabbit temporomandibular joint; 4) To elucidate the sustained release of growth factors and signal pathway of composite material. This project based on four aspects will provide theory that indicate the regeneration of cartialge defect, the molecular mechanism of chondrogenic ability and the way of degradability of highly elastic porous graphene scaffold combined with autologous concentrated growth factors.

关节软骨缺损严重影响患者生活质量，使用具有持续成软骨活性且力学性能匹配的生物材料来再生软骨，是解决这一临床难题的最有效途径。已知石墨烯具有良好力学性能、吸附性和生物相容性，提示其再生软骨潜力。我们预初实验已制备出能模拟关节软骨力学性能的高弹性石墨烯支架材料，然而如何赋予其持续成软骨活性？能否利用石墨烯卓越吸附性来缓释生长因子，获得持续成软骨活性的生物材料，用于关节软骨修复及其机制研究，尚不清楚。基于石墨烯强大吸附能力，推测其能有效缓释自体浓缩生长因子来促进软骨再生。为验证这一假说，本课题通过：1)制备复合材料，检测其理化性能；2)研究其生物相容性、降解性和软骨生物活性；3)评价其再生动物关节软骨的能力；4)证实其缓释自体浓缩生长因子能力及成软骨信号通路。从复合材料特性-软骨生物活性-组织修复-成软骨机制这四层次深入探索，揭示高弹性石墨烯多孔支架复合自体浓缩生长因子的软骨再生作用及机制。

关节软骨缺损严重影响患者生活质量，使用具有持续成软骨活性且力学性能匹配的生物材料来再生软骨，是解决这一临床难题的最有效途径。已知石墨烯具有良好力学性能、吸附性和生物相容性，具有再生软的巨大骨潜力。通过冷冻浇注法成功制备高弹性石墨烯多孔支架，具有高度弹性的多孔结构（>90%的孔隙率和140-180μm的孔径），它对多种生物酶都是稳定的，并能在生理盐水中反复压缩后迅速恢复形状（重复压缩后保持大于75%的应力）。材料具有良好的生物相容性和成软骨活性，支架上的软骨细胞中的II型胶原、SOX-9和聚集蛋白聚糖基因均上调，表明软骨生成增强。我们进行了体内研究，植入体内8周后，可以看到软骨样新生软骨组织长满支架材料内部，软骨基质有序分布，新生组织表达II型胶原蛋白、聚集蛋白聚糖和SOX-9等软骨特异性蛋白。MMP-13（胶原酶-3）、MMP-1（胶原酶-1）和MMP-8（胶原酶-3）的基因表达显著上调，这些胶原酶促进了对II型胶原的切割。TIMP-1和TIMP-3的表达也显著增高，表明支架可以促进TIMP-1和TIMP-3基因的表达抑制软骨基质降解。展现使用具有稳定和可调结构的高弹性石墨烯多孔支架，揭示其高速且平衡的软骨基质重塑，证明了软骨细胞在迁移到支架中时保持稳定的表型，为软骨修复的支架设计提供了新策略，为关节软骨缺损修复提供新一代安全而有效的支架材料。