双向梯度软骨支架的构建及关节软骨组织工程的实验研究

Significant limitations in using tissue engineered scaffold for cartilage regenerative are poor cartilage-to-bone integration and hyaline cartilage regeneration. The extra-cellular matrix (ECM) compositions, mechanical properties and cellular organization vary in a gradient pattern, therefore, it is necessary to immobilized the gradients of biological cues in the scaffolds to guide the cell-scaffold interaction. Current approaches mainly rely on the integration of multiple cell types or growth factor gradients within multilayered 3D scaffolds. Strategies based on multilayered constructs have restricted potentials for generating continuous, graded interfaces due to inherent discontinuities across the dissimilar materials. In this study, we immobilized bi-direction transforming growth factor-β1/ bone morphogenetic protein-2 (TGF-β1/BMP-2) within hydrogel scaffolds using diffuse printing method. In vitro cell culture is finally conducted to reveal the differentiation of bone marrow stem cells (BMSCs) on the gradient scaffolds. cartilage regeneration in femoral full-thickness cartilage defects in New Zealand White rabbits with the gradients immobilized scaffolds are also investigated. This would open a novel technology to immobilize gradients of growth factors within scaffolds and demonstrate the significant role of introducing gradients of TGF-β1/BMP-2 into scaffolds in promoting cartilage-to-bone integration and hyaline cartilage regeneration.

具有软骨诱导活性的生物材料，通过调动内源性骨髓基质干细胞（BMSCs）修复关节软骨缺损，具有临床应用前景。但存在着软骨-骨间的界面耦合效果不理想以及纤维而非透明软骨修复等亟待解决的难点。由于软骨各层细胞和基质的种类、结构和形态呈梯度分布，因此，在一定空间和浓度下使支架能够对细胞提供连续梯度分布的生物信号刺激已成为必要条件。针对目前关节软骨损伤修复材料仿生程度低、梯度生物信号负载技术缺乏等挑战，本项目拟合成带有侧基双键功能基团的嵌段共聚物，通过电化学手段，制备出带有双向连续梯度分布的TGF-β1/BMP-2水凝胶支架，研究该支架对BMSCs的响应和协调关系，及对兔膝关节软骨缺损修复的效果。项目预期将揭示梯度仿生模拟对关节软骨再生的重要意义。本项目的研究成果有望解决传统软骨支架不能完全恢复正常生理状态软骨的组织学及与周围组织整合不良的难点。

骨关节病是一种由于关节软骨进行性破坏引起关节结构和功能损害的疾病，是中老年致残最主要的原因，也是人类健康面临的重大危害之一。我国每年由退变、创伤和各种其它病因引起的骨关节疾病患者高达600余万人。同时随着我国人均寿命延长和社会人口老龄化，骨关节病的发病率还将进一步增高。伴随着骨关节病的发病率增高，社会及个人医疗负担大幅增长。骨关节病的典型病理改变都以不同程度的关节软骨缺损为特征，因此，迫切需要寻找和发展新的治疗方法和技术修复缺损的关节软骨。 . 本实验利用SF差异吸附，将BMP-2来源的短肽梯度负载于支架上，体内及体外实验验证了其软骨的能力。. 在该国家自然科学基金的资助下，我们发表SCI论文4篇，中文核心期刊2篇，其中5篇为第一作者或通讯作者，并申请国家实用新型专利1项，目前等待审批中，力争早期将研究成果进行转化。