Tendon-bone junction healing by injectable bioactive thermo-sensitive hydrogel based on inspiration of tendon derived stem cell

The rotator cuff repaired construct must establish a contiguous and functioning tendon-bone junction (TBJ) to provide adequate stability. However, fibrocartilage deficiency and bone loss were hardly reversed after physical suture, especially in chronic rotator cuff tear. In this study, we synthesized an injectable methylcellulose (MC)/polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP)-based thermo-sensitive hydrogel, which delivered kartogenin (KGN)-loaded mesoporous bioactive glass nanoparticles (MBGs). Physicochemical studies the revealed phase transition temperatures of 35 °C and its ability to induce chondrogenesis and osteogenesis differentiation of tendon derived stem cells (TDSCs). Furthermore, experiments in rabbit chronic rotator cuff tear (RCT) model confirmed the fibrocartilage and bone layer regenerative capability of the injected bioactive hydrogel, which could in turn support the ultimate tensile stress of the repaired rotator cuff. The bioactive agents-loaded hydrogel reported in this study is a valuable addition to the arsenal of biomaterials in applications to chronic tendon-bone junction injuries.