丝蛋白软骨支架力学特性及其对关节软骨原位再生的影响

Mechanical properties of silk fibroin cartilage scaffolds and its influence in situ regeneration of articular cartilage

目的探讨组织工程软骨支架降解过程中的力学保持性及其对软骨原位再生效果的影响。方法采用低温冷冻凝胶策略制备具有物理化学双交联结构的丝蛋白(SF)支架,在此基础上,运用扫描电镜、力学测试和组织学方法表征了支架的微观形貌、降解过程中的力学性能、体内组织相容性和软骨原位再生效果。结果物理化学双交联SF支架相较于普通冷冻干燥法制备的支架,呈现出更均匀的空隙结构,体现更优异的弹性和韧性,并且在降解过程中保持了结构完整性和力学稳定性。大鼠皮下试验结果表明,SF支架植入28 d后无明显异物反应,与周围组织融合良好。兔关节软骨缺损模型试验表明,SF支架能够维持稳定的力学微环境,促进软骨新基质的形成并实现软骨原位再生。结论SF支架降解过程中的力学保持性对于软骨新基质的形成具有重要作用。

Objective To explore the mechanical retention of tissue-engineered cartilage scaffolds during degradation and its effect on the in situ regeneration effect of cartilage.Methods Silk protein(SF)scaffolds with physicochemical double-crosslinked structure were prepared by low-temperature freezing gel strategy,based on which the micro-morphology,mechanical properties during degradation,in vivo histocompatibility and in situ regeneration of cartilage of the scaffolds were characterized by scanning electron microscopy,mechanical testing and histological methods.Results The physicochemical double-crosslinked SF scaffolds prepared presented a more uniform void structure,embodied superior elasticity and toughness,and maintained structural integrity and mechanical stability during degradation compared with those prepared by ordinary freeze-drying method.The results of the subcutaneous test in rats showed that the SF scaffolds had no obvious foreign body reaction 28 d after implantation and were well integrated with the surrounding tissues.In the rabbit articular cartilage defect model,the SF scaffold was able to maintain a stable mechanical microenvironment,promote the formation of cartilage neo-matrix and realize cartilage regeneration in situ.Conclusion The mechanical retention of SF scaffolds during degradation plays an important role in the formation of new cartilage matrix.