gms | German Medical Science

79. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

30.04. - 04.05.2008, Bonn

Effects of the glucocorticoid dexamethasone on gene expression of relevant members of the GDNF- und NGF-families in the auditory nerve of deafened rats

Meeting Abstract

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  • corresponding author Kirsten Wissel - HNO MHH, Hannover
  • Patrick Wefstaedt - Tierärztliche Hochschule Hannover, Hannover
  • Thomas Lenarz - Med. Hochschule Hannover, Hannover
  • Timo Stöver - Med. Hochschule Hannover, Hannover

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. 79. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. Bonn, 30.04.-04.05.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. Doc08hnod268

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Veröffentlicht: 22. April 2008

© 2008 Wissel et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen ( Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.



The benefit of the cochlea implant (CI) is depending on the number of surviving spiral ganglion neurons (SGN) and an efficient nerve-electrode interaction indicating that side effects as like connective tissue formation around the electrode or induction of inflammation have to be reduced. Neurotrophic factors (NTF) are known to enhance SGN survival, whereas glucocorticoids, i.e. dexamethasone (Dex), are potential anti-inflammatory agents. However, protective or toxic effects of glucocorticoids on SGN directly remains to be elucidated.

Method: The gene expression profile of relevant NTF (artemin (ART), GDNF, BDNF), as well of the glucocorticoid receptor GR1 and the inducible nitric oxide synthase iNOS were determined in the auditory nerve (AN) of normal hearing and deafened rats with and without Dex application, respectively, by semiquantitative RT-PCR.

Results: Our data revealed significant upregulation of iNOS in the AN of normal hearing rats treated with Dex. Also, higher mRNA levels were found in deafened rats injected with Dex and those without further treatment, as well in normal hearing rats following perilymphe injection (as control). GR1 showed significant downregulation in deafened rats, but increased gene expression in the other animal groups. ART, GDNF and BDNF revealed upregulated gene expression profiles for all animal groups, independently of the hearing status and the Dex treatment.

Conclusion: In the context of apoptosis it could not be demonstrated that application of Dex to the inner ear has beneficial effects on SGN. However, it has to be considered that the injection procedure alone may induce apoptosis or inflammation. The increase of NTF expression indicate that they play key roles in protection of SGN and counteract the apoptosis signaling.

Unterstützt durch: EU-project "Bioear"