Pirfenidone Injection to Prevent Vocal Fold Scarring in a Canine Model: A Pilot Preclinical Study

Area of Science:

• Otolaryngology
• Regenerative Medicine
• Fibrosis Research

Background:

• Vocal fold (VF) scarring after laser cordectomy can impair voice quality.
• Current treatments for VF scarring are limited.
• Pirfenidone (PFD) is an antifibrotic agent with potential therapeutic applications.

Purpose of the Study:

• To investigate the safety and efficacy of pirfenidone (PFD) injection for preventing vocal fold (VF) scarring post-laser cordectomy in a canine model.
• To determine safe PFD concentrations for VF injection.
• To evaluate PFD's preventive effects on VF scarring and vibratory function.

Main Methods:

• Toxicity assessment involved injecting varying PFD concentrations into canine VFs, followed by histological evaluation.
• Efficacy testing utilized PFD injections (1.0 and 2.5 mg/mL) prior to laser cordectomy, with controls receiving saline or no treatment.
• Assessments included laryngoscopy, high-speed imaging for vibratory function, and histological/immunohistochemical analyses for fibrosis markers (collagen type I and α-smooth muscle actin).

Main Results:

• PFD concentrations up to 2.5 mg/mL were found to be safe, showing complete epithelial healing.
• PFD injection, particularly at 2.5 mg/mL, significantly reduced VF scarring and collagen deposition compared to controls.
• High-speed imaging revealed improved vibratory amplitudes in PFD-treated VFs, indicating preserved vocal fold function.

Conclusions:

• Pirfenidone injection prior to laser cordectomy shows promise in mitigating vocal fold scarring in a canine model.
• PFD treatment may help preserve vocal fold vibratory function after surgical intervention.
• These findings support the potential of PFD as a preventive antifibrotic strategy in vocal fold surgery.