Structural and functional vocal fold epithelial integrity following injury.

OBJECTIVES/HYPOTHESIS An intact epithelium is an important part of vocal fold defense. Damage to the epithelium can compromise vocal fold homeostasis and protection of the host tissue from viral and bacterial invasion. Elucidating the effects of damage on epithelial architectural and barrier integrity provides insight into the role of epithelium in protecting vocal folds. Using an animal model, we evaluated the time course of structural and functional epithelial restoration following injury. STUDY DESIGN Prospective, controlled animal study. METHODS Forty rats underwent surgery to remove vocal fold mucosa unilaterally. Larynges were harvested at five time intervals between 3 to 90 days postinjury and were prepared for histological and permeability analyses. RESULTS Rapid restoration of structural integrity was demonstrated by return of a multilayerd epithelium, intercellular junctions, and basement membrane at 5 days postinjury. Atypical epithelial permeability was observed up to 5 weeks postinjury. CONCLUSION Restoration of epithelial barrier integrity lags epithelial structural restoration. Consequently, epithelial regeneration cannot be equated with return of functional barrier integrity. Rather, ongoing leakiness of regenerated epithelium indicates that vocal folds remain at risk for damage, pathogen invasion, and remodeling postinjury. LEVEL OF EVIDENCE N/A. Laryngoscope, 124:2764-2769, 2014.