Objectives/Hypothesis-We investigated the hypothesis that 30 minutes of raised intensity phonation alters transcript levels of vocal fold intercellular tight junction proteins and disrupts the vocal fold epithelial barrier.Study Design-Prospective animal study. Methods-EighteenNew Zealand white breeder rabbits were randomly assigned to receive 30 minutes of raised intensity phonation or approximation of the vocal folds without phonation. Quantitative polymerase chain reaction (qPCR) was used to investigate transcript levels of the epithelial intercellular tight junction proteins, occludin and zonula occludin-1 (Z0-1), and the adherens junction proteins β-catenin and E-cadherin. Structural alterations to the vocal fold epithelium were further examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results-MannWhitney U revealed significantly decreased occludin (P = .016) and β-catenin (P = .016) gene expression from rabbits undergoing raised intensity phonation, compared to control. There were no significant differences in Z0-1 and E-Cadherin gene expression between groups (P >.025). SEM revealed significant obliteration, desquamation, and evidence of microhole formation in rabbit vocal folds exposed to raised intensity phonation, compared to control, while TEM revealed dilated intercellular morphology between groups.Conclusions-Results provide support for the hypothesis that a transient episode of raised intensity phonation alters transcript levels of vocal fold intercellular tight junction proteins and disrupts integrity of the epithelial barrier. The loss of barrier integrity may have significant consequences on epithelial defenses and compromise protection of the underlying mucosa from damage secondary to prolonged vibration exposure.

Protease-activated receptors (PARs) play critical roles in hemostasis in vertebrates including zebrafish. However, the zebrafish gene classification appears to be complex and the expression patterns of par genes are not established. Based on analyses of genomic organization, phylogenetics, protein primary structure and protein internalization, we report the identification of four zebrafish PARs: par1, par2a, par2b, and par3. This classification differs from one reported previously. We also show that these genes have distinct spatiotemporal expression profiles in embryos and larvae – with par1, par2a and par2b expressed maternally and ubiquitously during gastrula stages and their expression patterns refined at later stages, and par3 expressed only in 3-day old larvae. Notably, the expression patterns of zebrafish par1 and par2b resemble those of their mammalian counterparts, suggesting that receptor function is conserved among vertebrates. This conservation is supported by our findings that Par1 and Par2b are internalized following exposure to thrombin and trypsin respectively.