Effects of Raised Phonation on Vocal Fold Gene Expression

Abstract

Investigate the effects of modal and raised intensity phonation on messenger RNA (mRNA) expression of the vocal fold in an in-vivo rabbit model. 2) Collect preliminary data to provide direction to future biochemical studies. METHODS: Ten New Zealand white rabbits were assigned to receive experimentally induced modal or raised intensity phonation for 30 minutes. A separate control group of five rabbits received sham surgery. Vocal folds were harvested post-procedure and real-time PCR was used to investigate mRNA expression of Interleukin-1beta (IL-1B), Transforming Growth Factor-beta1 (TGF-B1), and Cyclooxygenase-2 (COX-2). One-way analysis of variance (ANOVA) tests were used to investigate differences in gene expression across groups. Alpha was adjusted to .016 to control for type I error. Significant main effects were further examined using Tukeys post-hoc tests. RESULTS: ANOVA revealed a significant main effect for IL-1B, TGF-B1, and COX-2 between groups (p Ͻ .0001). Pairwise comparisons revealed that the expression of IL-1B increased significantly during raised intensity phonation, compared to modal phonation and sham-control (p Ͻ .0001); TGF-B1 increased significantly during raised intensity phonation, compared to modal phonation (p Ͻ .0001) and shamcontrol (p ϭ .002); and COX-2 increased significantly during raised intensity phonation, compared to modal phonation and sham-control (p Ͻ .0001). CONCLUSIONS: Results provide preliminary data on the effects of raised intensity phonation on inflammatory mRNA expression in an in-vivo rabbit model. Ultimately, this model will be used to investigate clinical observations, such as toolong and too-loud, which are terms frequently used to describe the pathophysiology of dysphonia to patients.