Histologic investigation of hyperphonated canine vocal cords.

Area of Science:

• Laryngology and Voice Science
• Animal Models in Biomedical Research
• Histopathology and Ultrastructural Analysis

Background:

• Understanding acute vocal cord injury from excessive phonation is crucial but hindered by the lack of suitable animal models.
• Previous research faced limitations in studying vocal abuse mechanisms due to inadequate experimental setups.
• The larynx and vocal cord function are vital for communication, making injury research a significant area.

Purpose of the Study:

• To develop and describe a novel canine model for inducing acute vocal cord injury through controlled excessive phonation.
• To investigate the histological and ultrastructural changes in vocal cords following experimentally induced phonotrauma.
• To provide a reproducible model for future studies on vocal cord injury and healing.

Main Methods:

• A canine model was established using a constant airflow delivered subglottally to induce phonation.
• Dogs were subjected to phonation for durations of 2 and 4 hours.
• Histologic techniques, including scanning and transmission electron microscopy, were employed to analyze vocal cord damage.

Main Results:

• Histological examination revealed significant surface damage to the vocal cords, including loss of microridges and epithelial desquamation.
• Ultrastructural analysis demonstrated injury extending into the lamina propria, with collagen fibers detaching from the basement membrane.
• Standard microscopy identified edema, but more subtle damages required advanced electron microscopy techniques for detection.

Conclusions:

• The developed canine model effectively replicates acute vocal cord injury caused by excessive phonation.
• This model allows for detailed investigation of phonotrauma at both surface and deeper tissue levels.
• The findings provide a foundation for further research into the pathophysiology and treatment of vocal cord injuries.