Histological effect of basic fibroblast growth factor on chronic vocal fold scarring in a rat model

Abstract

Objectives. Vocal fold scarring is one of the most challenging laryngeal disorders to treat and there are currently no consis­tently effective treatments available. Our previous studies have shown the therapeutic potential of basic fibroblast growth factor (bFGF) for vocal fold scarring. However, the histological effects of bFGF on scarred vocal fold have not been elucidated. The aim of this study was to examine the histological effects of bFGF on chronic vocal fold scarring. Methods. Sprague-Dawley rats were divided into phosphate buffered saline (sham) and bFGF groups. Unilateral vocal fold stripping was performed and the drug was injected into the scarred vocal fold for each group 2 months postopera­tively. Injections were performed weekly for 4 weeks. Two months after the last injection, larynges were harvested and histologically analyzed. Results. A significant increase of hyaluronic acid was observed in the vocal fold of the bFGF group compared with that of the sham group. However, there was no remarkable change in collagen expression nor in vocal fold contraction. Conclusion. Significant increase of hyaluronic acid by local bFGF injection was thought to contribute to the therapeutic effects on chronic vocal fold scarring.