The PLGA/TCP Scaffold Loaded with Tendon Stem Cells Contributes to the Tendon-Bone Healing of Rotator Cuff Tear in Rabbits

Abstract

Background: The postoperative healing of rotator cuff tear (RCT) often presents challenges. Poly (lactic-co-glycolic acid)/tricalcium phosphate (PLGA/TCP) scaffold is a composite biomaterial for repairing bone defect. This study aimed to investigate the impact of tendon stem cells (TDSCs)/PLGA/TCP composite scaffold on a rabbit model of RCT. Methods: After induction using osteogenic, adipogenic and chondrogenic medium, TDSCs differentiation was achieved. The multi-directional differentiation of TDSCs was confirmed through colony formation and staining with alizarin red, oil red, and toluidine blue. Quantitative real-time polymerase chain reaction was utilized to assess the expressions of stemness, osteogenesis, and tendon-related genes. TDSCs were cultured in PLGA/TCP scaffold, and their attachment, markers, and viability were evaluated using immunofluorescence and cell counting kit-8 assay. The rabbit RCT model was made. The morphology and tensile strength of tendon-bone healing were assessed by hematoxylin-eosin, masson, dil staining and tendon stretch assay. Quantification of β-catenin protein was realized by western blot. Results: The obtained TDSCs were identified as having the ability of multi-directional differentiation and stemness. CD73, CD90, and CD105 were positive and CD45 was negative in TDSCs. The multi-directional differentiation ability of TDSCs was improved on PLGA/TCP scaffold. The TDSC/PLGA/TCP composite scaffold promoted tendon-bone healing, fibrocartilage mineralization and formation, the expressions of osteogenic and tendon-related genes. Furthermore, it significantly promoted β-catenin expression, the invasive number of TDSCs, the ultimate load and stiffness of healing tendon. Conclusions: The loading of TDSCs further optimized the role of PLGA/TCP scaffold in promoting rotator cuff tendon-bone surface healing, which was closely related to the expression of β-catenin protein.