Histological changes in rats after implantation of vitreous-cryopreservation tissue engineered tendon

Background: The technique of vitreous cryopreservation applied to preserve tissue engineered tendon has the practicability and application prospects, and is required for further research. Objective: To investigate the effects of in vivo implantation of vitreous-cryopreservation tissue engineered tendon on repairing the tendon defects of the rats. Methods: Sixty-four adult Sprague Dawley rats were randomly divided into two groups, vitreous-cryopreservation tissue engineered tendons and fresh tissue engineered tendons without cryopreservation were implanted respectively. The 5 mm tendon defects models were prepared in the middle part of Achilles tendons of the rats, and the tissue engineered tendons were implanted. At 2, 4, 6 and 8 weeks after surgery, the general morphology and histological changes of the implanted tendons and surrounding tissues were observed. Results and Conclusion: No significant differences in general morphology and histological change of the implanted tendons and surrounding tissues were observed between two groups. At 2 and 4 weeks after surgery, the implanted tendon materials were degraded gradually, and were infiltrated and surrounded by a large number of inflammatory cells and proliferous fibrous connective tissues. At 6 and 8 weeks after surgery, the implanted tendons were degraded and replaced by a large number of regenerative collagenous fiber tissues; the morphology and orientation of the collagenous fiber tissues were similar to those of normal tendon tissues. The tendon defects of the rats were repaired basically. The results indicate the in vivo implantation of vitreous-cryopreservation tissue engineered tendons can repair the tendon defects of the rats.