Scar formation in mice deafened with kanamycin and furosemide.
In mammals, hair cell loss is irreversible and leads to hearing loss. To develop and test the functioning of different strategies aiming at hair cell regeneration, animal models of sensorineural hearing loss are essential. Although cochleae of these animals should lack hair cells, supporting cells should be preserved forming an environment for the regenerated hair cells. In this study, we investigated how ototoxic treatment with kanamycin and furosemide changes the structure of cochlear sensory epithelium in mice. The study also compared different tissue preparation protocols for scanning electron microscopy (SEM). Cochleae were collected from deafened and nondeafened mice and further processed for plastic mid modiolar sections and SEM. For comparing SEM protocols, cochleae from nondeafened mice were processed using three protocols: osmium-thiocarbohydrazide-osmium (OTO), tannic acid-arginine-osmium, and the conventional method with gold-coating. The OTO method demonstrated optimal cochlear tissue preservation. Histological investigation of cochleae of deafened mice revealed that the supporting cells enlarged and ultimately replaced the lost hair cells forming types 1 and 2 phalangeal scars in a base towards apex gradient. The type 3 epithelial scar, flattened epithelium, has not been seen in analysed cochleae. The study concluded that mice deafened with kanamycin and furosemide formed scars containing supporting cells, which renders this mouse model suitable for testing various hair cell regeneration approaches. Microsc. Res. Tech. 79:766-772, 2016. © 2016 Wiley Periodicals, Inc.
Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Magdalena
M
Żak
Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Cynthia A
CA
van der Linden
Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Aren
A
Bezdjian
Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Ferry G
FG
Hendriksen
Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Sjaak F L
SF
Klis
Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Wilko
W
Grolman
D000818:Animals; D004195:Disease Models, Animal; D005665:Furosemide / Q000633:toxicity*; D006198:Hair Cells, Auditory / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D006319:Hearing Loss, Sensorineural / Q000139:chemically induced* / Q000473:pathology*; D007612:Kanamycin / Q000633:toxicity*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D009925:Organ of Corti / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure
D007612:Kanamycin; D005665:Furosemide
SEM; hair cells; hearing loss; mouse model; stereocilia