生物活性微球调控软骨细胞定向积聚的实验研究

Cell aggregation effectively facilitates cartilage formation and regeneration through regulating functionality of chondrocytes / progenitors during both embryonic development and adulthood. However, lack of strategy to regulate cell aggregation hinders progresses of cartilage regenerative medicine. Based on previous research and a broad literature review, we hypothesize that bioactive microspheres could promote cartilage regeneration through regulating proper cell aggregations in scaffolding biomaterials. Although biodegradable polymeric microspheres have been broadly investigated, difficulties in control of morphologies and bioactive sites as well as formation of effective concentration gradients limit their applications in cell aggregation. In current study, bioactive polymeric microspheres will be fabricated with optimized experimental parameters, while effects of the bioactive microspheres on cell aggregation and chondrogenesis will be evaluated. Scaffolding biomaterials integrated with bioactive microspheres could not only enhance chondrogenesis potentially, but also establish a novel research model for in vitro chondrogenesis. Furthermore, it could facilitate advance of regenerative medicine and exploration of mechanism behind.

在胚胎发育和成体软骨中，细胞积聚通过调节软骨细胞分化状态有效促进了软骨形成和再生，但在三维生物支架材料中尚缺乏有效的细胞积聚手段，阻碍了软骨再生医学的发展。本研究在实验室既往研究基础和广泛文献总结的基础上提出：生物活性微球可能通过定向调控支架材料中的细胞积聚过程而促进软骨再生。生物降解高分子微球被广泛研究，但形貌控制、生物活性位点及生化因子浓度梯度方面的欠缺阻碍了它们在细胞积聚调控中的应用。本研究旨在探索制备生物活性高分子微球的实验条件，并检验生物活性微球对细胞积聚及软骨形成的调控作用。三维支架材料与生物活性微球的结合不仅有望进一步提升其成软骨能力，还可以为细胞积聚研究提供新的研究模型，促进软骨再生医学的发展及相关机理研究。

细胞积聚通过调节软骨细胞分化状态有效促进了软骨形成和再生，但在三维生物支架材料中尚缺乏有效手段主动调控细胞积聚，限制了分化效率。通过优化高分子的种类、分子量、溶剂性质、溶液浓度等制备参数，采用双乳液挥发法制备1.5%的PLGA多孔微球并以明胶修饰。这些微球能够在体外平面培养中促进细胞积聚。聚羟基丁酸/戊酸酯poly (β-hydroxybutyrateco-β-hydroxyvalerate)微球不仅能增强高分子支架材料力学性能，还能显著促进II型胶原和蛋白多糖的基因表达，显著提升了软骨细胞表型。在裸鼠皮下包埋实验中微球增强的多孔支架材料可以显著提升糖胺多糖的分泌。综上所述：在多孔支架材料中添加微球，不但可以调控力学性质，还能调控细胞积聚状态并提升细胞的软骨表型。未来对于单细胞的积聚状态与表型关系，还需深入探索。