Vocal fold wound healing after injection of human adipose-derived stem cells in a rabbit model

Conclusion: Injection of injured rabbit vocal folds with human adipose-derived stem cells (hADSCs) led to improved wound healing and fewer signs of scarring as demonstrated by a decreased collagen content in the treated folds compared with the untreated folds. hADSCs remained viable for up to 12 weeks in rabbit vocal folds. Objective: The aim of this study was to investigate the morphologic and histologic properties of scarred rabbit vocal folds following injection of hADSCs. Methods: This was a randomized, controlled animal study. Twenty-four vocal folds from 12 New Zealand rabbits were scarred using a CO(2) laser and injected with either hADSCs (left vocal fold) or phosphate-buffered saline (right vocal fold). Every 4 weeks for the first 12 weeks after injection, an endoscopic examination was performed to assess the morphology of the vocal folds. Twelve weeks later the animals were euthanized and the tissues were stained for histology. Results: In comparison with the right vocal folds, there was significantly less granulation tissue in the hADSCs-injected left vocal folds (p < 0.05). Histological examination revealed excessive collagen deposition and perichondral fibrosis in the right vocal folds, whereas the left vocal folds exhibited better wound healing and less collagen deposition (p < 0.05). Among the 12 specimens injected with hADSCs, 4 specimens demonstrated viable hADSCs under immunofluorescent cytochemistry.