Vitamin A deficiency causes metaplasia in vocal fold epithelium: A rat study

Objectives: The roles of vitamin A in the vocal fold epithelium are not well documented, although vitamin A has been used as a conservative treatment for laryngeal leukoplakia. The purpose of this study was to analyze the roles of vitamin A in vocal fold epithelial differentiation. Methods: Vitamin A-deficient (VAD) rats were generated, and the abnormality of their vocal fold epithelium was examined by hematoxylin and eosin staining and immunohistochemical analysis for keratin 10 and transglutaminase (TGase) 1. Results: The VAD experimental rats exhibited orthokeratosis of the vocal fold epithelium. Keratin 10 and TGase 1 were up-regulated in the epithelium of the VAD rats. Conclusions: It is suggested that vitamin A suppresses TGase 1 expression in normal vocal folds to inhibit keratinization, and that the TGase 1 up-regulation caused by vitamin A deficiency may be related to the formation of metaplasia in the laryngeal epithelium.