Hierarchical macro-microporous WPU-ECM scaffolds combined with Microfracture Promote in Situ Articular Cartilage Regeneration in Rabbits

Tissue engineering provides a promising avenue for treating cartilage defects.However,great challenges remain in the development of structurally and functionally optimized scaffolds for cartilage repair and regeneration.In this study,decellularized cartilage extracellular matrix(ECM)and waterborne polyurethane(WPU)were employed to construct WPU and WPU-ECM scaffolds by water-based 3D printing using low-temperature deposition manufacturing(LDM)system,which combines rapid deposition manufacturing with phase separation techniques.The scaffolds successfully achieved hierarchical macro-microporous structures.After adding ECM,WPU scaffolds were markedly optimized in terms of porosity,hydrophilia and bioactive components.Moreover,the optimized WPU-ECM scaffolds were found to be more suitable for cell distribution,adhesion,and proliferation than the WPU scaffolds.Most importantly,the WPU-ECM scaffold could facilitate the production of glycosaminoglycan(GAG)and collagen and the upregulation of cartilage-specific genes.These results indicated that the WPU-ECM scaffold with hierarchical macro-microporous structures could recreate a favorable microenvironment for cell adhesion,proliferation,differentiation,and ECM production.In vivo studies further revealed that the hierarchical macro-microporous WPU-ECM scaffold combined with the microfracture procedure successfully regenerated hyaline cartilage in a rabbit model.Six months after implantation,the repaired cartilage showed a similar histological structure and mechanical performance to that of normal cartilage.In conclusion,the hierarchical macro-microporous WPU-ECM scaffold may be a promising candidate for cartilage tissue engineering applications in the future.

中国人胫骨干相对于胫骨平台的偏心距

背景：带延长杆的胫骨假体已经应用于复杂的初次膝关节置换和膝关节翻修手术。多数这些假体的设计基于西方人群的解剖数据。我们进行了膝关节的形态学研究来了解中国人胫骨干和胫骨平台的位置关系。方法：本研究包含50位研究对象（25位男性和25位女性）。用MRI扫描膝关节和胫骨干近端。测量胫骨干轴线和胫骨平台中心的距离并将其定义为胫骨干相对于胫骨平台的偏心距。分别在3个截骨面上测量偏心距，由上而下分别为通过内侧胫骨平台软骨面下、软骨面下5mm和软骨面下10mm。同时测量胫骨平台的直径。结果：在由上而下的3个截骨面上，胫骨干的偏心距分别为（7．23±2．44）mm[内外方向为（3．40±1．94）mrn，前后方向为（6．22±2．05）mm]、（6．33±2．26）mm[内外方向为（3．14±2．04）mm，前后方向为（5．24±1．96）mm]和（4．75±2．07）mm[内外方向为（2．68±1．91）mm，前后方向为（3．46±2．03）mm]。在每一个截骨面上，男性的平均胫骨干偏心距均明显大于女性。结论：中国人胫骨干相对于胫骨平台的偏心距存在较大变异。胫骨干轴线位于胫骨平台中心的前外侧。