Effect of denervation on primate laryngeal muscles: a morphologic and morphometric study

Area of Science:

• Laryngeal anatomy and physiology
• Neuromuscular pathology
• Primate muscle biology

Background:

• Intrinsic laryngeal muscles are crucial for voice production.
• Understanding denervation effects is key for treating vocal cord dysfunction.
• Primate models offer insights into human laryngeal muscle responses.

Purpose of the Study:

• To investigate the temporal effects of denervation on primate intrinsic laryngeal muscles.
• To characterize the histological changes in different laryngeal muscle fiber types post-denervation.
• To determine the timeline for fibrosis development in denervated laryngeal muscles.

Main Methods:

• Histological analysis of primate laryngeal muscles (Type I and Type II fibers).
• Induction of denervation and examination at two, four, and eight weeks post-procedure.
• Comparative analysis of fiber size, inflammatory reactions, and fibrosis across different laryngeal muscles.

Main Results:

• Denervation caused Type II fiber shrinkage by two weeks.
• The thyroarytenoid muscle exhibited significant inflammation and size reduction at four weeks.
• All studied laryngeal muscles showed fibrosis by eight weeks post-denervation.

Conclusions:

• Laryngeal muscles demonstrate early signs of denervation within two weeks.
• Thyroarytenoid muscle undergoes inflammatory degeneration, distinct from other laryngeal muscles.
• Fibrosis is a terminal stage by eight weeks, with implications for clinical reinnervation strategies.