title: Dexamethasone suppresses cochlear Hes1 expression after noise exposure.
abstract: CONCLUSIONS
  Dexamethasone provides protection against noise-induced hearing loss (NIHL) possibly by suppressing cochlear Hes1 expression via a glucocorticoid receptor (GR)-dependent mechanism.
  
  
  OBJECTIVE
  The purpose of the present study was to explore whether hairy and enhancer of split 1 (Hes1) was involved in the protective effect of dexamethasone against NIHL.
  
  
  METHODS
  Guinea pigs, which were administered intraperitoneal injections of either saline, 1.0 mg/kg dexamethasone, 20.0 mg/kg RU38,486, or a combination of both drugs (dexamethasone plus RU38,486) for 5 consecutive days, were exposed to white-band noise (115 dB sound pressure level). The expression level of Hes1 in cochleae was compared using real-time RT-PCR and Western blot analysis.
  
  
  RESULTS
  Noise exposure for 3 h induced auditory brainstem response (ABR) threshold elevations, outer hair cell losses, and increase of Hes1 expression. Dexamethasone pretreatment prevented the NIHL with decreased Hes1 expression, which could be blocked by GR antagonist RU38,486.
authors.affiliation: Department of Otorhinolaryngology, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Yujian
authors.initials: Y
authors.lastname: Liu
authors.forename: Fanglu
authors.initials: F
authors.lastname: Chi
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Meiqin
authors.initials: M
authors.lastname: Yang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhu
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015153:Blotting, Western; D003051:Cochlea / Q000187:drug effects* / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006168:Guinea Pigs; D006317:Hearing Loss, Noise-Induced / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics*; D006727:Hormone Antagonists / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D015735:Mifepristone / Q000494:pharmacology; D011292:Premedication; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000893:Anti-Inflammatory Agents; D018398:Homeodomain Proteins; D006727:Hormone Antagonists; D015735:Mifepristone; D003907:Dexamethasone