Raised intensity phonation compromises vocal fold epithelial barrier integrity

Area of Science:

• Vocal fold physiology
• Epithelial biology
• Biophysics of voice production

Background:

• The vocal fold epithelium acts as a critical barrier against environmental insults.
• Intercellular tight junctions (TJs) and adherens junctions (AJs) are crucial for maintaining epithelial integrity.
• Understanding how phonotrauma affects these structures is vital for voice health.

Purpose of the Study:

• To test if 30 minutes of high-intensity phonation alters transcript levels of vocal fold TJ proteins.
• To determine if phonation disrupts the vocal fold epithelial barrier.
• To investigate the impact on occludin, zonula occludin-1 (ZO-1), β-catenin, and E-cadherin.

Main Methods:

• Prospective animal study involving 18 New Zealand white rabbits.
• Raised intensity phonation or vocal fold approximation without phonation.
• Quantitative polymerase chain reaction (qPCR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed.

Main Results:

• Significantly decreased gene expression of occludin and β-catenin in the phonation group (P = .016).
• No significant differences in ZO-1 and E-cadherin gene expression.
• SEM showed epithelial obliteration, desquamation, and microholes; TEM revealed dilated intercellular spaces.

Conclusions:

• Results support the hypothesis that high-intensity phonation transiently alters TJ protein transcript levels.
• Vocal fold phonotrauma disrupts epithelial barrier integrity.
• Compromised barrier function may increase susceptibility to damage from prolonged vibration.