A Comparison of the Localization of Integral Membrane Proteins in Human and Rabbit Vocal Folds

This study's objective was to identify and compare the localization of Aquaporin (AQP) 1, 4, 7, Na+/K + -ATPase, E-cadherin, zona occludin (ZO)-1, and occludin in human and rabbit vocal folds (VF)s to inform the design of future studies to explore the function of these proteins in the regulation of VF homeostasis.

Four human larynges and five New Zealand white rabbit larynges were used. Samples were immunolabeled for primary antibodies against AQP1, AQP4, AQP7, the alpha subunit of Na+/K + -ATPase, E-cadherin, and ZO-1 and occludin and then captured digitally using a Nikon Eclipse 90i microscope and Hamamatsu C10600 Camera. Two raters familiar with human and rabbit VF histology identified positive labeling in tissue structures, including the apical epithelium, basal epithelium/basement membrane, and lamina propria (LP).

Samples from both species showed positive labeling for AQP1 in the basal epithelium/basement membrane, superficial LP, and deep/intermediate LP. Aquaporin 4, Aquaporin 7, Na+/K + -ATPase, and E-cadherin were primarily localized to the epithelium of both species. Zona occludin-1 was primarily localized apical epithelium and the superficial LP of both species. Occludin was primarily present in the apical epithelium in rabbit samples but not human.

These data provide evidence of the presence of key ion transport channels and cell adhesion proteins in human and rabbit VFs. Aquaporin 1, 4, 7, Na+/K + -ATPase, E-cadherin, and ZO-1 were similarly localized in both species. These findings will be useful to investigators interested in the exploration of VF homeostasis and barrier integrity in future studies.

N/A Laryngoscope, 131:E1265-E1271, 2021.