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Subcutaneous Neurotrophin 4 Infusion Using Osmotic Pumps or Direct Muscular Injection Enhances Aging Rat Laryngeal Muscles
Published on: June 13, 2017
Changes in vocal fold gene expression and histology after injection augmentation in a recurrent laryngeal nerve
Ronit Malka1, Alisa Isaac2, Gabriela Gonzales2
1Department of Otolaryngology - Head and Neck Surgery, Brooke Army Medical Center, Joint Base San Antonio, Fort Sam Houston, TX, USA.
Objective:
To investigate changes in neuroregenerative pathways with vocal fold denervation in response to vocal fold augmentation.
Methods:
Eighteen Yorkshire crossbreed swine underwent left recurrent laryngeal nerve transection, followed by observation or augmentation with carboxymethylcellulose or calcium hydroxyapatite at two weeks. Polymerase chain reaction expression of genes regulating muscle growth (MyoD1, MyoG and FoxO1) and atrophy (FBXO32) were analysed at 4 and 12 weeks post-injection. Thyroarytenoid neuromuscular junction density was quantified using immunohistochemistry.
Results:
Denervated vocal folds demonstrated reduced expression of MyoD1, MyoG, FoxO1 and FBXO32, but overexpression after augmentation. Healthy vocal folds showed increased early and late MyoD1, MyoG, FoxO1 and FBXO32 expression in all animals. Neuromuscular junction density had a slower decline in augmented compared to untreated denervated vocal folds, and was significantly reduced in healthy vocal folds contralateral to augmentation.
Conclusion:
Injection augmentation may slow neuromuscular degeneration pathways in denervated vocal folds and reduce compensatory remodelling in contralateral healthy vocal folds.
