The integrative regeneration of both articular cartilage and subchondral bone remains an unmet clinical need due to the difficulties of mimicking spatial complexity in native osteochondral tissues for artificial implants. Layer-by-layer fabrication strategies, such as 3D printing, have emerged as a promising technology replicating the stratified zonal architecture and varying microstructures and mechanical properties. However, the dynamic and circulating physiological environments, such as mass transportation or cell migration, usually distort the pre-confined biological properties in the layered implants, leading to undistinguished spatial variations and subsequently inefficient regenerations. This study introduced a biomimetic calcified interfacial layer into the scaffold as a compact barrier between a cartilage layer and a subchondral bone layer to facilitate osteogenic–chondrogenic repair. The calcified interfacial layer consisting of compact polycaprolactone (PCL), nano-hydroxyapatite, and tasquinimod (TA) can physically and biologically separate the cartilage layer (TA-mixed, chondrocytes-load gelatin methacrylate) from the subchondral bond layer (porous PCL). This introduction preserved the as-designed independent biological environment in each layer for both cartilage and bone regeneration, successfully inhibiting vascular invasion into the cartilage layer and preventing hyaluronic cartilage calcification owing to devascularization of TA. The improved integrative regeneration of cartilage and subchondral bone was validated through gross examination, micro-computed tomography (micro-CT), and histological and immunohistochemical analyses based on an rat model. Moreover, gene and protein expression studies identified a key role of Caveolin (CAV-1) in promoting angiogenesis through the Wnt/β-catenin pathway and indicated that TA in the calcified layer blocked angiogenesis by inhibiting CAV-1.

中文翻译：

---

利用具有钙化界面层的 3D 打印仿生支架增强骨软骨再生

由于人工植入物难以模拟天然骨软骨组织的空间复杂性，因此关节软骨和软骨下骨的整合再生仍然是一个未满足的临床需求。逐层制造策略（例如 3D 打印）已成为一种有前途的技术，可以复制分层的区域结构以及不同的微观结构和机械性能。然而，动态和循环的生理环境，例如质量运输或细胞迁移，通常会扭曲分层植入物中预先限制的生物特性，导致不明显的空间变化和随后的低效再生。这项研究将仿生钙化界面层引入支架中，作为软骨层和软骨下骨层之间的致密屏障，以促进成骨-软骨修复。由致密聚己内酯（PCL）、纳米羟基磷灰石和他喹莫德（TA）组成的钙化界面层可以在物理和生物学上将软骨层（TA混合、软骨细胞负载明胶甲基丙烯酸酯）与软骨下结合层（多孔PCL）分离。这种引入为软骨和骨再生保留了各层设计的独立生物环境，成功抑制了血管侵入软骨层，并防止了由于TA断血管而导致的透明质软骨钙化。通过肉眼检查、显微计算机断层扫描 (micro-CT) 以及基于大鼠模型的组织学和免疫组织化学分析，验证了软骨和软骨下骨整合再生的改善。此外，基因和蛋白质表达研究确定了 Caveolin (CAV-1) 通过 Wnt/β-catenin 通路促进血管生成的关键作用，并表明钙化层中的 TA 通过抑制 CAV-1 来阻止血管生成。