Preparation of Decellularized Triphasic Hierarchical Bone-Fibrocartilage-Tendon Composite Extracellular Matrix for Enthesis Regeneration.

Tendon to bone (enthesis) rupture, which may cause disability and persistent pain, shows high rate of re-rupture after surgical repair. Tendon or enthesis scaffolds have been widely studied, but few of these materials can recapitulate the tissue continuity. Thus, this study is conducted to prepare a triphasic decellularized bone-fibrocartilage-tendon (D-BFT) composite scaffold. The D-BFT scaffold is developed using a combination of physical, chemical, and enzymatic treatments using liquid nitrogen, Triton-X 100, sodium-dodecyl sulfate, and DNase I, which effectively removes the cell components while preserving the biological composite and microstructure. Moreover, the mechanical properties of D-BFT are highly preserved and similar to those of the human Achilles tendon. Additionally, in vitro, mesenchymal stem cells (MSCs) adhered, proliferated, and infiltrated into the D-BFT scaffold, and MSC differentiation is confirmed by up-regulation of osteogenic-related and tenogenic-related genes. The repair outcomes are explored by applying the D-BFT scaffold in the model of femur-tibia defects in vivo, which shows good repair results. Thus, the D-BFT scaffold developed in this study is a promising graft for enthesis regeneration.