Abstract

Rapid and functional enthesis regeneration after rotator cuff tear (RCT) remains a challenge in clinic. Current tissue-engineering strategies for solving this challenge are focused on developing grafts with the mode of in-vitro loading cells on a scaffold. However, this mode is complicated and time-inefficient, moreover the preservation of this graft outside a cell incubator is highly inconvenient, thus limiting their clinical application. Developing a cell-free graft with chemotaxis to recruit postoperative injected cells may be a promising approach to solve these problems. Herein, we prepared a recombinant SDF-1α (termed as C-SDF-1α) capable of binding collagen and chemotaxis, which were then tethered on the collagen fibers of book-shaped decellularized fibrocartilage matrix (BDFM) to fabricate this cell-free graft (C-SDF-1α/BDFM). This C-SDF-1α/BDFM is noncytotoxicity and low-immunogenicity, allows synovium-derived mesenchymal stem cells (SMSCs) attachment and proliferation, and shows superior chondrogenic inducibility. More importantly, C-SDF-1α/BDFM released the tethered SDF-1α with a sustained release profile in-vitro and in-vivo, thus steadily recruiting chemokine (C-X-C motif) receptor 4 positive (CXCR4 + ) cells. Rats with RCT were repaired acutely with C-SDF-1α/BDFM together with postoperative CXCR4 + SMSCs injection (C-SDF-1α/BDFM + CXCR4 + SMSCs), BDFM in-vitro pre-loaded CXCR4 + SMSCs (BDFM/CXCR4 + SMSCs), or direct suture only (CTL). At postoperative 14-day, compared with BDFM/CXCR4 + SMSCs, C-SDF-1α/BDFM + CXCR4 + SMSCs showed a little more CXCR4 + SMSCs at the healing site. At postoperative week 4 or 8, rats treated with C-SDF-1α/BDFM + CXCR4 + SMSCs presented a similar RC healing quality as BDFM/CXCR4 + SMSCs, both of which were significantly better than the CTL. Collectively, compared with conventional BDFM/CXCR4 + SMSCs, C-SDF-1α/BDFM, as a cell-free graft with chemotaxis, could recruit postoperative injected CXCR4 + cells into the heal