Round window gentamicin application: an inner ear hair cell damage protocol for the mouse.
It is important to develop an inner ear damage protocol for mice that avoids systemic toxicity and produces damage in a relatively rapid fashion, allowing for study of early cellular and molecular mechanisms responsible for hair cell death and those that underlie the lack of hair cell regeneration in mammals. Ideally, this damage protocol would reliably produce both partial and complete lesions of the sensory epithelium. We present a method for in vivo induction of hair cell damage in the mouse via placement of gentamicin-soaked Gelfoam in the round window niche of the inner ear, an adaptation of a method developed to study hair cell regeneration in chicks. A total of 82 subjects underwent the procedure. Variable doses of gentamicin were used (25, 50, 100 and 200 microg). Saline-soaked Gelfoam, sham-operations and the contralateral, non-operated cochlea were used as controls. Survival periods were 1, 3 and 14 days. Damage was assessed on scanning electron microscopy. We found that this method produces relatively rapid hair cell damage that varies with dose and can extend the entire length of the sensory epithelium. In addition, this protocol produces no systemic toxicity and preserves the contralateral ear as a control.
Heydt
Jennifer L
JL
Department of Otolaryngology-Head and Neck Surgery, University of Washington, Box 356515, Seattle, WA 98195-7923, USA.
Cunningham
Lisa L
LL
Rubel
Edwin W
EW
Coltrera
Marc D
MD
D000818:Animals; D004398:Dyneins; D005781:Gelatin Sponge, Absorbable; D005839:Gentamicins / Q000008:administration & dosage / Q000633:toxicity*; D006198:Hair Cells, Auditory / Q000187:drug effects* / Q000293:injuries* / Q000378:metabolism / Q000648:ultrastructure; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000293:injuries / Q000378:metabolism / Q000648:ultrastructure; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects / Q000293:injuries / Q000378:metabolism / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008855:Microscopy, Electron, Scanning; D000081412:Myosin VIIa; D009218:Myosins / Q000378:metabolism; D012405:Round Window, Ear / Q000187:drug effects; D013997:Time Factors
D005839:Gentamicins; C000631456:Myo7a protein, mouse; D000081412:Myosin VIIa; D009218:Myosins; D004398:Dyneins