Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University , Nanjing, China .
Tissue Eng Part A. 2018 Nov;24(21-22):1680-1692. doi: 10.1089/ten.TEA.2018.0086. Epub 2018 Oct 19.
Repair of articular cartilage defects using bilayered scaffolds is problematic because tissue-engineered cartilage is prone to overgrowth toward subchondral bone, resulting in structural abnormalities of cartilage and subchondral bone. A "twice freeze-drying" technique was used to construct a dense isolation layer between the cartilage and subchondral bone layers in an integrated bilayered scaffold to prevent cartilage from excessive downgrowth. Briefly, beta-tricalcium phosphate was used for the subchondral bone layer of the scaffold, high-concentration chitosan/gelatin solution for the dense isolation layer, and low-concentration chitosan/gelatin solution for the cartilage layer. As controls, cell-free trilayered scaffolds, autologous osteochondral transplantation, and the bilayered scaffolds were used for repair of osteochondral defects. After 6 months, two of the eight goats in the bilayered scaffold group showed conspicuous cartilage downgrowth, whereas no excessive downgrowth of cartilage was observed in the trilayered scaffold group. Moreover, there was no difference in the repair efficacy between the trilayered scaffold and mosaicplasty group. The results confirmed that the trilayered scaffold effectively prevented cartilage downgrowth with better cartilage repair.
使用双层支架修复关节软骨缺损存在问题，因为组织工程软骨容易向软骨下骨过度生长，导致软骨和软骨下骨的结构异常。采用“两次冻干”技术在整合的双层支架中构建软骨和软骨下骨层之间的致密隔离层，以防止软骨过度向下生长。简要地说，β-磷酸三钙用于支架的软骨下骨层，高浓度壳聚糖/明胶溶液用于致密隔离层，低浓度壳聚糖/明胶溶液用于软骨层。作为对照，使用无细胞三层支架、自体骨软骨移植和双层支架修复软骨下骨缺损。6 个月后，双层支架组的 8 只山羊中有 2 只出现明显的软骨向下生长，而在三层支架组中未观察到软骨过度向下生长。此外，三层支架组和马赛克plasty 组的修复效果没有差异。结果证实，三层支架能有效防止软骨向下生长，软骨修复效果更好。
