Auto-inflammatory challenge of the endolymphatic sac – Cochlear damage measured by distortion product oto-acoustic emissions. (August 2015)

• Record Type: Journal Article
• Authors: Larsen, Michael; Friis, Morten; Karlsen, Charlotte Vestrup; Poulsen, Steen Seier; Lund, Søren Peter; Qvortrup, Klaus
• Is Part Of: Acta oto-laryngologica. Volume 135:Number 8(2015)
• Page Start: 758
• Page End: 764
• Publication Date: 2015-08
• Subjects: Otolaryngology -- Periodicals; Ear -- Diseases -- Periodicals; Throat -- Diseases -- Periodicals; Otolaryngology -- Electronic Resources; Otorhinolaryngologic Diseases; 617.8
• DOI: 10.3109/00016489.2015.1032433
• Languages: English
• ISSNs: 0001-6489

Abstract

<abstract> <title>Abstract</title> <p> <italic>Conclusion:</italic> 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. <italic>Objectives:</italic> 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. <italic>Methods:</italic> 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. <italic>Results:</italic> 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 (<italic>p</italic> < 0.05). The same test showed a 2.5 dB decrease from 2 to 5 kHz (<italic>p</italic> < 0.01). Immunological active cells were observed in the endolymphatic sac in most of the immunized rats.</p> </abstract>