Tissue-engineering approaches have a great potential to improve the treatment of
tendon injuries that affect millions of people. The present study tested the hypothesis that introduction of a
tendon derived stem/progenitor cell (TSC) sheet accelerates
tendon healing and
tendon regeneration in a rat model. TSC sheets were produced on temperature-responsive culture dishes. Then, they were grafted on unwounded Achilles
tendons and at sites of a 3 mm of Achilles
tendon defect. At 2 and 4 weeks after implantation
tendons were examined by histology, immunohistochemistry, transmission electron microscopy (TEM) and mechanical testing. The results showed that the implanted TSC sheet remained stably attached on the
tendon surface at 4 weeks after implantation. Moreover, in the
tendon defect model,
tendon defect area where TSC sheet was implanted was well regenerated and had better organized collagen fibers with elongated spindle shaped cells, compared to relatively disorganized collagen fibers and round shaped cells in the control group. TEM observations revealed longitudinally aligned collagen fibers and thick collagen fibrils in the TSC sheet implanted group. Finally, at 4 weeks mechanical property of the TSC sheet implanted
tendon had better ultimate load than the control. In conclusion, this study demonstrates the feasibility of implanting TSC sheets on
tendons
in vivo. Introduction of the cell sheets into a
tendon defect significantly improved histological properties and collagen content at both 2 and 4 weeks after implantation, indicating that TSC sheets may effectively promote
tendon remodeling in the early stages of
tendon healing.
Statement of Significance
Tendon injury is a highly prevalent clinical problem that debilitates millions of people worldwide in both occupational and athletic settings. It also costs billions of healthcare dollars in treatment every year. In this study, we showed the feasibility of using tendon derived stem cell sheet to deliver biologically active tenogenic-constructs and promote tendon regeneration. This work has the potential to impact the orthopaedic surgery and sports medicine fields in the treatment of tendon injury.