title: Auto-inflammatory challenge of the endolymphatic sac--Cochlear damage measured by distortion product oto-acoustic emissions.
abstract: CONCLUSIONS
  Twenty-five rats were challenged by an immunologic attack of the endolymphatic sac. After 6 months, distortion product oto-acoustic emissions (DPOAE) revealed a dysfunction of the outer hair cells and immunological active cells were observed in the endolymphatic sac. This information could contribute to the understanding of Ménière's disease.
  
  
  OBJECTIVE
  This study investigated if an autoimmune challenge of the endolymphatic sac could affect DPOAE output measurements in rats. Also, a potential autoimmune cell infiltration of the endolymphatic sac was investigated.
  
  
  METHODS
  Eighteen Lewis rats were immunized with a crude endolymphatic sac extract in complete Freund's adjuvant. Seven control animals were injected with Freund's adjuvant in saline. Cochlear damage was estimated by DPOAE dynamics 3 weeks and 6 months after the immunization. Infiltrative cells in the endolymphatic sac were investigated with transmission electron microscopy.
  
  
  RESULTS
  The hearing assessment 6 months after immunization revealed a reduction of the DPOAE, on the full range of frequencies (2-63 kHz) in an average of the mean, of 2 dB ± 1.1 in the immunized group compared to the controls (p < 0.05). The same test showed a 2.5 dB decrease from 2 to 5 kHz (p < 0.01). Immunological active cells were observed in the endolymphatic sac in most of the immunized rats.
authors: Department of Biomedical Sciences, University of Copenhagen.
authors: Michael
authors: M
authors: Larsen
authors: Morten
authors: M
authors: Friis
authors: Charlotte Vestrup
authors: CV
authors: Karlsen
authors: Steen Seier
authors: SS
authors: Poulsen
authors: Søren Peter
authors: SP
authors: Lund
authors: Klaus
authors: K
authors: Qvortrup
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D015551:Autoimmunity; D003051:Cochlea / Q000648:ultrastructure; D004195:Disease Models, Animal; D004712:Endolymphatic Sac / Q000503:physiopathology / Q000648:ultrastructure*; D008575:Meniere Disease / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D046529:Microscopy, Electron, Transmission; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D051381:Rats; D011917:Rats, Inbred Lew
keywords: Meniere’s disease; autoimmunity; distortion product oto-acoustic emissions (DPOAE); endolymphatic sac; rat