title: Effect of geranylgeranylacetone on gentamycin ototoxicity in rat cochlea culture.
abstract: OBJECTIVE
  Geranylgeranylacetone (GGA), an anti-ulcer drug, has been reported to induce heat shock proteins (HSPs) in several animal organs. Purpose of this study was to investigate whether GGA has protective effect on gentamycin (GM) ototoxicity and whether it induces HSP70 in rat cochlea.
  
  
  METHODS
  We used cochlea explant culture from postnatal 5-day rat. Explants were pre-incubated with GGA, then incubated with GM and GGA. The number of surviving outer hair cells (OHCs) labeled by phalloidin was counted to evaluate the protective effect of GGA. The expression of HSP70 in whole cochlea tissue was investigated by immunoblot analysis.
  
  
  RESULTS
  The number of surviving OHCs was significantly high in GGA 10(-5)M group compared to GM only group and GGA 10(-6)M group. In the immunoblot analysis, HSP70 levels in GGA added groups were slightly high compared to simple culture group, but much lower than those in heat shock group.
  
  
  CONCLUSIONS
  It was suggested that GGA-induced HSP70, and had partial protective effects on GM ototoxicity in the cochlea. GGA has possibility to be safe and useful treatment drug for cochlea disorder.
authors.affiliation: Department of Otolaryngology, Kitasato University, School of Medicine, 1-15-1 Kitasato, Sagamihra, Kanagawa 228-8555, Japan. sanohj@med.kitasato-u.ac.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Sano
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoneda
authors.forename: Hitoo
authors.initials: H
authors.lastname: Iwase
authors.forename: Akihiko
authors.initials: A
authors.lastname: Itoh
authors.forename: Daimon
authors.initials: D
authors.lastname: Hashimoto
authors.forename: Makito
authors.initials: M
authors.lastname: Okamoto
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000890:Anti-Infective Agents / Q000009:adverse effects* / Q000037:antagonists & inhibitors*; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003051:Cochlea / Q000378:metabolism*; D004224:Diterpenes / Q000008:administration & dosage / Q000494:pharmacology*; D005839:Gentamicins / Q000009:adverse effects* / Q000037:antagonists & inhibitors*; D018840:HSP70 Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects; D015151:Immunoblotting; D051381:Rats; D017208:Rats, Wistar; D046509:Tissue Culture Techniques
chemical_list: D000890:Anti-Infective Agents; D000897:Anti-Ulcer Agents; D004224:Diterpenes; D005839:Gentamicins; D018840:HSP70 Heat-Shock Proteins; C031049:geranylgeranylacetone