Gene expression of transforming growth factor-beta1 and hepatocyte growth factor during wound healing of injured rat vocal fold

Abstract

Objectives/hypothesis: To investigate the expression of genes coding transforming growth factor (TGF)-beta1, hepatocyte growth factor (HGF), and c-Met, its membrane-spanning tyrosine kinase receptor, during the inflammatory, proliferative, and remodeling phases of wound healing in the injured rat vocal fold.

Study design: Prospective animal study.

Methods: Thirty five rats were involved in this study. Bilateral vocal fold wounds were created in 30 rats. Injured vocal fold specimens were harvested on postinjury day 1, 3, 7, 14, 28, and 56. Real-time polymerase chain reaction (PCR) was used to quantify mRNA expression of TGF-beta1, HGF, and c-Met. Five uninjured rats were used to establish PCR control.

Results: Results of analysis of variance revealed a significant main effect for TGF-beta1 (P = .000), HGF (P = .000), and c-Met (P = .000) expression across time points. Post-hoc testing revealed that TGF-beta1 expression increased significantly on postinjury day 7 (P = .001) compared to control. HGF expression decreased significantly on postinjury day 1 (P = .001), and increased significantly on postinjury day 14 (P = .000). c-Met expression decreased significantly on postinjury day 1 (P = .000), day 3 (P = .000), and day 56 (P = .000), and increased significantly on postinjury day 28 (P = .000).

Conclusions: Results revealed time-dependent changes in the regulation of genes coding TGF-beta1, HGF, and c-Met during wound healing in the injured rat vocal fold. These patterns of gene expression correspond well with previously reported histologic changes of the rat vocal fold after injury.