title: Vibration induced hearing loss in guinea pig cochlea: expression of TNF-alpha and VEGF.
abstract: Transcranial vibration was applied for seven animals at a frequency of 250 Hz for 15 min, and five animals were used as normal controls to investigate cellular and molecular mechanism linked to vibration-induced hearing loss in animal model. Compound action potential (CAP) thresholds were measured by round window niche electrode. The expression of tumour necrosis factor alpha (TNF-alpha) and its receptors (TNF R1, TNF R2), vascular endothelium growth factor (VEGF) and its receptors (VEGF R1, VEGF R2) were analysed by immunohistochemistry. Transcranial vibration caused expression of TNF-alpha, TNF R1 and TNF R2 in the cochlea and the expression of TNF R2 was stronger than that of TNF R1. Vibration also induced VEGF and VEGF R2 expression in the cochlea. The average immediate hearing loss was 62 dB and after three days still 48 dB. It is concluded that transcranial vibration as during temporal bone drilling produces cochlear shear stress that is connected with up-regulation of TNF-alpha and its receptors. Also VEGF and VEGF R2 are up-regulated. These responses may be linked to both the damage and repair process of the cochlea.
authors.affiliation: Department of Otolaryngology, Tampere University Hospital, Finland. jing.zou@uta.fi
authors.forename: Jing
authors.initials: J
authors.lastname: Zou
authors.forename: Ilmari
authors.initials: I
authors.lastname: Pyykkö
authors.forename: Päivi
authors.initials: P
authors.lastname: Sutinen
authors.forename: Esko
authors.initials: E
authors.lastname: Toppila
mesh_terms: D000818:Animals; D003051:Cochlea / Q000378:metabolism*; D006168:Guinea Pigs; D034381:Hearing Loss / Q000209:etiology* / Q000378:metabolism* / Q000503:physiopathology; D007150:Immunohistochemistry; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000378:metabolism; D013314:Stress, Mechanical; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D014732:Vibration
chemical_list: D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2