title: Myosin VIIa and otoferlin in cochlear inner hair cells have distinct response to ototoxic exposure.
abstract: CONCLUSIONS
  Ototoxic gentamicin exposure does not disrupt the expression of myosin VIIa in the inner hair cells (IHCs) of mice, whereas gentamicin ototoxicity causes altered expression of otoferlin in IHCs, as well as parallel hearing threshold shifts.
  
  
  OBJECTIVE
  To explore whether myosin VIIa and otoferlin in IHCs have different responses to gentamicin ototoxicity.
  
  
  METHODS
  Lower dose treatment (100 mg/kg): adult C57 mice were continuously injected intraperitoneally with gentamicin once a day for 14 consecutive days. Dose-dependent gentamicin treatment: mice were injected intraperitoneally with differing doses (100, 200, and 300 mg/kg) once a day for 2 consecutive days. The hearing thresholds were detected by auditory brainstem response (ABR). Immunostaining and Western blotting were utilized to measure the manner of expression of myosin VIIa and otoferlin in IHCs.
  
  
  RESULTS
  Lower dose treatment: There were no significant differences among the control (day 0), and 4, 7, and 14 days after the ototoxicity exposure (p > 0.05). Dose-dependent gentamicin treatment: There were no significant differences among the control, 100, 200, and 300 mg/kg groups after the ototoxicity exposure (p > 0.05). In contrast, we found an altered expression of otoferlin in IHCs among the control (day 0), and 4, 7, and 14 days of exposure, when the mice were exposed to gentamicin ototoxicity (p > 0.05).
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital , Beijing.
authors.forename: Ke
authors.initials: K
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Ji
authors.forename: YiCe
authors.initials: Y
authors.lastname: Xu
authors.forename: XiaoYu
authors.initials: X
authors.lastname: Wang
authors.forename: ZhaoHui
authors.initials: Z
authors.lastname: Hou
authors.forename: ShiMing
authors.initials: S
authors.lastname: Yang
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000633:toxicity*; D001309:Auditory Threshold / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005839:Gentamicins / Q000008:administration & dosage / Q000633:toxicity*; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins / Q000187:drug effects* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D000081412:Myosin VIIa; D009218:Myosins / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D008565:Membrane Proteins; C000631456:Myo7a protein, mouse; D000081412:Myosin VIIa; C516233:otoferlin protein, mouse; D009218:Myosins
keywords: Gentamicin ototoxicity; hearing loss; hearing threshold shift