title: Suppression of apoptosis occurs in the cochlea by sound conditioning.
abstract: Apoptosis plays a critical role in the pathogenesis of noise-induced hearing loss. The goal of this study was to determine if apoptotic pathways are suppressed by sound conditioning. Sound conditioning is a pretreatment to low-level non-damaging sound that protects against a subsequent damaging acoustic trauma. Sound conditioning protects against hair cell death and thereby preserves hearing after a subsequent acoustic trauma. Using a combination of immunocytochemical and Western blotting techniques we show that acoustic trauma causes the release of cytochrome c from the mitochondria into the cytoplasm, and a decrease in bcl-2 immunoreactivity in the outer hair cells. Sound conditioning was found to trigger a protection against these detrimental changes. These data suggest that bcl-2 plays an important role in the regulation of hair cell death, and provides evidence that bcl-2 acts as an inducible neuroprotective gene that is upregulated by sound conditioning.
authors.affiliation: Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Xianzhi
authors.initials: X
authors.lastname: Niu
authors.forename: Ruijin
authors.initials: R
authors.lastname: Shao
authors.forename: Barbara
authors.initials: B
authors.lastname: Canlon
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D003051:Cochlea / Q000737:chemistry / Q000378:metabolism*; D003213:Conditioning, Psychological / Q000502:physiology*; D006168:Guinea Pigs; D013016:Sound