Tendon-Derived Stem Cell Sheet Promotes Early-Stage Tendon-Bone Healing.

OBJECTIVES: To investigate the role of a tendon-derived stem cell (TDSC) sheet in tendon-bone healing within an extra-articular bone tunnel rat model. METHODS: Sprague-Dawley rats were randomly assigned to experimental and control groups. The superficial flexor tendon, with or without a TDSC sheet, was transplanted into a 1.0-mm diameter bone tunnel in the proximal tibia. The impact of the TDSC sheet on tendon-bone healing was assessed through radiological analysis, histological staining, and biomechanical testing. RESULTS: The TDSC sheet significantly enhanced tendon-bone healing, as evidenced by higher tunnel bone mineral density and bone volume/total volume at 4 weeks post-operation. Hematoxylin-eosin staining revealed that the TDSC sheet promoted the alignment of perpendicular collagen fibers connecting the tendon to the bone, along with Sharpey's fibers and new bone formation at the tendon-bone junction at both 4 and 8 weeks. Additionally, Masson's staining demonstrated that the tendon-bone interface was filled with abundant collagen fibers, with a significantly higher proportion of collagen fiber area in the TDSC sheet group compared to the control group at both 4 and 8 weeks. CONCLUSION: The TDSC sheet may enhance tendon-bone healing in the early stages, providing a potential therapeutic approach to accelerate tendon-bone remodeling.