Department of Sports Medicine, Huashan Hospital, Shanghai, China.
Am J Sports Med. 2020 Jul;48(8):1826-1836. doi: 10.1177/0363546520917684. Epub 2020 May 26.
Graft bridging is used in massive rotator cuff tear (MRCT); however, the integration of graft-tendon and graft-bone is still a challenge.
A co-electrospinning nanoscaffold of polycaprolactone (PCL) with an "enthesis-mimicking" (EM) structure could bridge MRCT, facilitate tendon regeneration, and improve graft-bone healing.
Controlled laboratory study.
First, we analyzed the cytocompatibility of the electrospinning nanoscaffolds, including aligned PCL (aPCL), nonaligned PCL (nPCL), aPCL-collagen I, nPCL-collagen II, and nPCL-nanohydroxyapatite (nHA). Second, for the EM condition, nPCL-collagen II and nPCL-nHA were electrospun layer by layer at one end of the aPCL-collagen I; for the control condition, the nPCL was electrospun on the aPCL. In 40 mature male rats, resection of both the supraspinatus and infraspinatus tendons was performed to create MRCT, and the animals were divided randomly into EM and control groups. In both groups, one end of the layered structure was fixed on the footprint of the rotator cuff, whereas the other end of the layered structure was sutured with the tendon stump. The animals were euthanized for harvesting of tissues for histologic and biomechanical analysis at 4 weeks or 8 weeks postoperatively.
All scaffolds showed good cytocompatibility in vitro. The graft-tendon tissue in the EM group had more regularly arranged cells, denser tissue, a significantly higher tendon maturing score, and more birefringence compared with the control group at 8 weeks after operation. Newly formed fibrocartilage could be observed at the graft-bone interface in both groups by 8 weeks, but the EM group had a higher graft-bone healing score and significantly more newly formed fibrocartilage than the control group. An enthesis-like structure with transitional layers was observed in the EM group at 8 weeks. Biomechanically, the values for maximum failure load and stiffness of the tendon-graft-bone complex were significantly higher in the EM group than in the control group at 8 weeks.
The co-electrospinning nanoscaffold of aPCL-collagen I could be used as a bridging graft to improve early graft-tendon healing for MRCT in a rat model and enhance early enthesis reconstruction in combination with a multilayered structure of nPCL-collagen II and nPCL-nHA.
We constructed a graft to bridge MRCT, enhance graft-tendon healing and graft-bone healing, and reconstruct the enthesis structure.
移植物桥接技术用于治疗巨大肩袖撕裂（massive rotator cuff tear，MRCT）；然而，移植物-肌腱和移植物-骨的整合仍然是一个挑战。
具有“腱骨结合部模拟”（enthesis-mimicking，EM）结构的聚己内酯（polycaprolactone，PCL）共电纺纳米支架可桥接 MRCT，促进肌腱再生，并改善移植物-骨愈合。
对照实验室研究。
首先，我们分析了电纺纳米支架的细胞相容性，包括定向聚己内酯（aligned PCL，aPCL）、非定向聚己内酯（non-aligned PCL，nPCL）、aPCL-胶原 I、nPCL-胶原 II 和 nPCL-纳米羟基磷灰石（nano-hydroxyapatite，nHA）。其次，对于 EM 条件，nPCL-胶原 II 和 nPCL-nHA 分别在 aPCL-胶原 I 的一端逐层电纺；对于对照条件，nPCL 则在 aPCL 上进行电纺。在 40 只成熟雄性大鼠中，同时切除冈上肌和冈下肌肌腱以造成 MRCT，然后将动物随机分为 EM 组和对照组。在两组中，分层结构的一端固定在肩袖的足迹上，而另一端与肌腱残端缝合。术后 4 周或 8 周时，处死动物以采集组织进行组织学和生物力学分析。
所有支架在体外均显示出良好的细胞相容性。与对照组相比，术后 8 周时，EM 组的移植物-肌腱组织中细胞排列更规则，组织更密集，肌腱成熟评分更高，双折射更明显。两组在术后 8 周时均可观察到移植物-骨界面处有新形成的纤维软骨，但 EM 组的移植物-骨愈合评分更高，新形成的纤维软骨也明显多于对照组。在 EM 组中，术后 8 周时观察到类似腱骨结合部的结构，具有过渡层。生物力学方面，EM 组的肌腱-移植物-骨复合体的最大失效载荷和刚度值在术后 8 周时明显高于对照组。
aPCL-胶原 I 的共电纺纳米支架可用作桥接移植物，以改善大鼠模型中 MRCT 的早期移植物-肌腱愈合，并结合 nPCL-胶原 II 和 nPCL-nHA 的多层结构增强早期腱骨结合部重建。
我们构建了一种移植物来桥接 MRCT，增强移植物-肌腱和移植物-骨的愈合，并重建腱骨结合部结构。
