OBJECTIVES - The overarching goal of this line of research is to translate basic fibroblast growth factor (bFGF) treatment for vocal fold scarring into practical clinical use. In a previous canine investigation, we demonstrated that bFGF improves phonation threshold pressure, mucosal wave amplitude, and histologic measures in vocal folds treated after injury. In the present study, we studied the effects of bFGF on gene expression of the extracellular matrix and growth factors in rat vocal fold fibroblasts.
METHODS - Fibroblasts harvested from the vocal folds of 5 rats were treated with 3 concentrations of bFGF (0, 10, and 100 ng/mL). The fibroblasts were collected at 24 hours and 72 hours after bFGF administration. Quantitative polymerase chain reaction was then used to investigate the gene expression of the investigated growth factors and extracellular matrices.
RESULTS - The results revealed significantly down-regulated expression of procollagen I and significantly up-regulated expression of hyaluronic acid synthase (HAS) 2 and fibronectin in fibroblasts treated with bFGF. The administration of bFGF also resulted in the up-regulation of bFGF and hepatocyte growth factor (HGF). No changes in the expression of HAS-1, tropoelastin, or procollagen III were observed between the treatment and control conditions.
CONCLUSIONS - Treatment with bFGF induces the down-regulation of procollagen I and the up-regulation of HAS-2 in vocal fold fibroblast cell cultures. These gene expression alterations to key mediators of the wound healing process may translate into potential benefits in the remediation of vocal fold injury. The up-regulation of HGF, an antifibrotic effector molecule, may demonstrate additional benefits by optimizing the wound healing environment and by accelerating the wound repair cascade. These findings may provide fuel for additional discoveries into the development of growth factor therapy for the treatment of vocal fold scar.