Upregulation of HSP by geranylgeranylacetone protects the cochlear lateral wall from endotoxin-induced inflammation
- 作者：Michihiko Sone ; Hideo Hayashi ; Hiroshi Yamamoto ; Tatsuya Hoshino ; Toru Mizushima and Tsutomu Nakashima
- 关键词：GGA ; HSP ; Inner ear ; Otitis media ; Cochlear trauma
- 刊名：Hearing Research
- 出版年：2005
- 期刊代码：111_03785955
- 类别：med
- 出版时间：2005
- 卷：204
- 期：1-2
- 页码：140-146
- 文件大小：420 K
摘要
We investigated whether an acyclic polyisoprenoid antiulcer drug, geranylgeranylacetone (GGA), induces the expression of HSP70 in the rat cochlea. Immunoblotting revealed upregulation of HSP70 in the cochlea at 12 h after transtympanic (local) or oral (systemic) administration of GGA, and this increased at 24 h after administration. Positive immunohistochemical staining of HSP70 was observed in the hair cells, the spiral ganglion, the stria vascularis, the spiral ligament, and the perivascular portion of modiolar vessels. We therefore subsequently studied the effects of GGA as an HSP-inducer on inner ear trauma due to inflammation. Damage to the lateral wall due to inflammation induced by lipopolysaccharide inoculation was protected against by pretreatment with GGA, as assessed physiologically by measurement of cochlear blood flow and morphologically by electron microscopy. The results of the present study suggest that GGA can protect the cochlea against other injuries including those induced by noise, ototoxic drugs, and ischemia by upregulating HSP70.