激光熔融3D打印金属植入物表面不同孔隙大小促进肌腱长入的机制研究

At present, the repair of tendons and ligaments clinically over-limit joint replacement is performed by mechanical suture. Long-term is the connection through scar tissue, which reduces the functional properties of the tendon and increases the risk of avulsion fracture. This issue uses laser melting 3D printing technology to design and print scaffolds with different pore sizes on the metal surface. In addition, TGF-β1 is most closely related to the scar formation during tendon repair. It regulates the metabolism of extracellular matrix mainly through the Smad pathway and promotes scar hyperplasia. The issue firstly studied the relationship between the molecular mechanism of scar hyperplasia at the interface between the different pore size and the tendon metal by in vitro and in vivo experiments. Further, an acute injury repair model of rabbit supraspinatus tendon was constructed. TGF-β1 receptor signaling inhibitors are used to inhibit the TGF-β1/Smad signaling pathway. The combination of Poly(amino acid) hydrogel carrying TGF-β1 receptor inhibitor and controlling the pore size of the scaffold produces a synergistic inhibitory effect on the inhibition pathway of scar hyperplasia. This promotes the growth of tendons into the tendon-metal bonding interface of the metal scaffold. Further explore the biomechanical and molecular biological changes of the cells and extracellular matrix in tendon-metal bonding interface. It provides a feasible method and theoretical basis for the clinical study of tendon growth into metal prosthesis.

目前临床超限关节置换附近肌腱和韧带的修复早期是通过机械地缝合，长期是通过瘢痕组织的连接，降低了肌腱的功能特性，增加了撕脱断裂的风险。本课题利用激光熔融3D打印技术设计并打印出金属表面不同孔隙大小的支架。另外，肌腱修复时，TGF-β1与瘢痕形成关系最为密切，它主要通过Smad通路调控细胞外基质的代谢，促进瘢痕增生，课题先通过体内外实验研究不同孔径大小的支架在分子机制方面与肌腱-金属结合界面瘢痕增生的关系。进一步构建兔冈上肌肌腱急性损伤修复模型，用TGF-β1受体抑制剂，抑制TGF-β1/Smad信号通路，联合应用搭载TGF-β1受体抑制剂的聚氨基酸凝胶和支架孔径大小控制，两种不同的方式对瘢痕增生的抑制途径产生协同抑制效应，促进肌腱在肌腱-金属结合部长入金属网格并探讨肌腱-金属结合界面细胞和细胞外基质的生物力学及分子生物学的改变，为临床研究肌腱长入金属假体提供可行办法及理论基础。

应用激光熔融3D打印，制备以正方体为单体的4种不同孔径的钛合金金属支架，使其互相连通的孔隙率达到70%以上，通过支架性质表征，体外、体内实验和力学实验，得出结论，随着支架孔径的降低，实际孔径在202微米的钛合金支架有最强的骨整合能力，且与周围骨固定最为牢固，当实际孔径继续减小时，由于血管很难长入支架，缺少氧气和营养物质，新生骨组织少且矿化减少，但是不影响新生骨组织的长入深度。为临床寻找钛合金植入物表面最佳骨长入多孔支架的孔隙设计提供参考。.另一方面，恶性骨肿瘤治疗目的是在提高患者生存率和保留肢体的前提下尽量恢复肢体的功能, 目前人工假体植入后的肌腱固定仍未找到合适的办法。研究和解决肌腱和假体之间的生物固定是恢复肢体功能的关键。为了增加肌腱纤维长入支架并减少瘢痕组织生成，本研究制备出以正方体为单体的实际孔大小分别为657.65，527.15,348.68,169.20微米的四组圆柱体支架。通过细胞实验，成纤维细胞能够正常的生长并爬入支架内，并伸出伪足附着在金属颗粒之间。成纤维细胞在实际孔大小在527.15微米的支架内粘附及长入的数量最多。将各组支架应用到兔冈上肌腱急性损伤模型中，用micro CT和硬组织切片染色的方法分析各组支架肌腱长入的情况，得出实际孔径在527.15微米是最佳的促进肌腱长入的钛合金表面孔隙大小。为临床设计肿瘤假体表面肌腱附着处孔隙大小提供参考。