title: Hair cell counts in a rat model of sound damage: Effects of tissue preparation & identification of regions of hair cell loss.
abstract: Exposure to intense sound can damage or kill cochlear hair cells (HC). This loss of input typically manifests as noise induced hearing loss, but it can also be involved in the initiation of other auditory disorders such as tinnitus or hyperacusis. In this study we quantify changes in HC number following exposure to one of four sound damage paradigms. We exposed adult, anesthetized Long-Evans rats to a unilateral 16 kHz pure tone that varied in intensity (114 dB or 118 dB) and duration (1, 2, or 4 h) and sacrificed animals 2-4 weeks later. We compared two different methods of tissue preparation, plastic embedding/sectioning and whole mount dissection, for quantifying hair cell loss as a function of frequency. We found that the two methods of tissue preparation produced largely comparable cochleograms, with whole mount dissections allowing a more rapid evaluation of hair cell number. Both inner and outer hair cell loss was observed throughout the length of the cochlea irrespective of sound damage paradigm. Inner HC loss was either equal to or greater than outer HC loss. Increasing the duration of sound exposures resulted in more severe HC loss, which included all HC lesions observed in an analogous shorter duration exposure.
authors: Neuroscience Graduate Program, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Otolaryngology and Head and Neck Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA. Electronic address: cneal@kumc.edu.
authors: Christopher
authors: C
authors: Neal
authors: Neuroscience Graduate Program, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Otolaryngology and Head and Neck Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors: Stefanie
authors: S
authors: Kennon-McGill
authors: Neuroscience Graduate Program, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Otolaryngology and Head and Neck Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors: Andrea
authors: A
authors: Freemyer
authors: Department of Otolaryngology and Head and Neck Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors: Axel
authors: A
authors: Shum
authors: Department of Otolaryngology and Head and Neck Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors: Hinrich
authors: H
authors: Staecker
authors: Department of Otolaryngology and Head and Neck Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA. Electronic address: ddurham@kumc.edu.
authors: Dianne
authors: D
authors: Durham
mesh_terms: D000818:Animals; D001309:Auditory Threshold; D003051:Cochlea / Q000503:physiopathology*; D006198:Hair Cells, Auditory / Q000473:pathology*; D006199:Hair Cells, Auditory, Inner / Q000473:pathology; D018072:Hair Cells, Auditory, Outer / Q000473:pathology; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology*; D008297:Male; D009622:Noise; D010969:Plastics; D051381:Rats; D020318:Rats, Long-Evans; D015203:Reproducibility of Results; D013016:Sound; D014021:Tissue Preservation / Q000379:methods
chemical_list: D010969:Plastics
keywords: Cochleogram; Hair cell; Hearing loss; Sound exposure