gms | German Medical Science

77. 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.

24.05. - 28.05.2006, Mannheim

Expression of hypoxia-dependent genes in the newborn rat cochlea

Meeting Abstract

  • corresponding author presenting/speaker Birgit Mazurek - Charité - University Medicine Berlin, Berlin, Germany
  • Cornelia Rheinländer - Charité - University Medicine Berlin, Berlin, Germany
  • Frank-Uwe Fuchs - Charité - University Medicine Berlin, Berlin, Germany
  • author Nyamaa Amarjargal - Charité - University Medicine Berlin, Berlin, Germany
  • Ute Ungethüm - Charité - University Medicine Berlin, Berlin, Germany
  • author Heidemarie Haupt - Charité - University Medicine Berlin, Berlin, Germany
  • Thomas Kietzmann - Technical University, Kaiserslautern, Germany
  • author Johann Gross - Charité - University Medicine Berlin, Berlin, Germany

German Society of Otorhinolaryngology, Head and Neck Surgery. 77th Annual Meeting of the German Society of Otorhinolaryngology, Head and Neck Surgery. Mannheim, 24.-28.05.2006. Düsseldorf, Köln: German Medical Science; 2006. Doc06hno034

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Veröffentlicht: 7. September 2006

© 2006 Mazurek et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction: Under hypoxic/ischemic conditions, the transcription factor HIF-1 (hypoxia-inducible factor 1) regulates the expression of a number of genes that are involved in glucose supply, growth, metabolism, oxidoreduction processes and blood supply. Because of the role that hypoxia and ischemia have to play in the pathogenesis of tinnitus and hearing loss, the HIF-1 activity and the expression of HIF-1-dependent genes were analyzed in the cochlea under these conditions.

Methods: A single-cell culture was used for analyzing HIF-1 expression in the following cochlear regions: organ of Corti (OC), stria vascularis (SV) and modiolus (MOD). The mRNA expressions of HIF-1 target genes were analyzed in the organotypic culture under the following conditions: normoxia, culturing and hypoxia using microarray techniques (RN U-34 chip, Affymetrix).

Results: The HIF-1 activation was found to be similar in ischemia (hypoxia + glucose deficiency) and pure hypoxia with the highest increase found in MOD and OC. The HIF-1alpha mRNA levels were found to be higher in the SV than in the OC and MOD. During culturing, HIF-1alpha mRNA and HIF-1-dependent genes are up-regulated. HIF-1 target genes, which are involved in the glucose metabolism, the activity of insulin-like growth factor, the ferric transport, the blood supply and, especially, the scavening of oxygen free radicals show region specific expression patterns. Some of the genes involved in the growth of the cochlea are down-regulated.

Conclusions: The present data underline the role that radical forming processes have to play in the inner ear damage. For experimental studies, it is important to note that the organotypic culture may be coupled with a high expression of HIF-dependent genes.