Histologic Changes of Vocal Fold Aging in a Rat Model

Abstract

Background and Objectives Aging causes atrophy in mucosa of vocal folds, resulting in various deleterious changes in phonation. Eventually, these changes impair an elderly individual’s ability to communicate with others and affect their quality of life. This investigation was carried out to determine the morphological characteristics of vocal folds in two different aged groups of rats, and to perform a validation of a rat model of age-related changes in larynx. Subjects and Method Larynges were obtained from 12 rats, of which 6 rats were 6 months old and the others 18 months old. The middle portion of each vocal folds were stained with haematoxylin and eosin (H&E), Masson’s trichrome (MT), Alcian blue (AB) and compared. Results Extracellular matrix in lamina propria of vocal folds presented lower density in 18 months-old rats than in 6 months-old rats (p＜0.05). Also more severe fibrosis was observed in 18 months-old rats than in 6 months-old rats (p＜0.05). Six months-old rats showed higer concentration of hyaluronic acid than did 18 months-old rats (p＜0.05). Conclusion Aged vocal folds showed increased fibrosis and decreased density of collagen and hyaluronic acids in the lamina propria compared to young vocal fold.