Histologic Characterization of Rat Vocal Fold Scarring

TLDR

The study aimed to clarify rat vocal fold scarring by examining changes in hyaluronic acid, collagen, and fibronectin. Unilateral vocal fold stripping was performed, and larynges were harvested at 2, 4, 8, and 12 weeks post‑operation for histological analysis using Alcian blue, trichrome, and immunofluorescence staining of collagen I, III, and fibronectin. Scarred vocal folds showed reduced hyaluronic acid and increased collagen I and III at all time points; collagen I declined until 8 weeks then plateaued, collagen III remained stable, and fibronectin peaked at 4 weeks before returning to control levels, indicating that tissue remodeling slows around two months after wounding.

Abstract

This study aimed to clarify the characteristics of rat vocal fold scarring by examining the alteration of key components in the extracellular matrix: hyaluronic acid, collagen, and fibronectin. Under monitoring with a 1.9-mm-diameter telescope, unilateral vocal fold stripping was performed, and larynges were harvested at 2, 4, 8, and 12 weeks after operation. The vocal folds were histologically analyzed with Alcian blue stain, trichrome stain, and immunofluorescence of collagen type I, collagen type III, and fibronectin. The scarred vocal folds showed less hyaluronic acid and more collagen types I and III than did the controls at all time points. Type III was stable for 12 weeks, while type I declined until 8 weeks and thereafter remained unchanged. Fibronectin increased for 4 weeks and then decreased; it was close to the control level at 8 and 12 weeks. These results suggest that the tissue remodeling process in scarred vocal folds slows down around 2 months after wounding.