OBJECTIVE: Recent findings support the crucial role of microcirculatory disturbance and ischemia for hearing impairment especially after noise-induced hearing loss (NIHL). The aim of this study was to establish an animal model for in vivo analysis of cochlear microcirculation and hearing function after a loud noise to allow precise measurements of both parameters in vivo. STUDY DESIGN: Randomized controlled trial. Setting. Animal study. Subjects and Methods. After assessment of normacusis (0 minutes) using evoked auditory brainstem responses (ABRs), noise (106-dB sound pressure level [SPL]) was applied to both ears in 6 guinea pigs for 30 minutes while unexposed animals served as controls. In vivo fluorescence microscopy of the stria vascularis capillaries was performed after surgical exposure of 1 cochlea. ABR measurements were derived from the contralateral ear. RESULTS: After noise exposure, red blood cell velocity was reduced significantly by 24.3% (120 minutes) and further decreased to 44.5% at the end of the observation (210 minutes) in contrast to stable control measurements. Vessel diameters were not affected in both groups. A gradual decrease of segmental blood flow became significant (38.1%) after 150 minutes compared with controls. Hearing thresholds shifted significantly from 20.0 ± 5.5 dB SPL (0 minutes) to 32.5 ± 4.2 dB SPL (60 minutes) only in animals exposed to loud noise. CONCLUSION: With regard to novel treatments targeting the stria vascularis in NIHL, this standardized model allows us to analyze in detail cochlear microcirculation and hearing function in vivo.
OBJECTIVE: Recent findings support the crucial role of microcirculatory disturbance and ischemia for hearing impairment especially after noise-induced hearing loss (NIHL). The aim of this study was to establish an animal model for in vivo analysis of cochlear microcirculation and hearing function after a loud noise to allow precise measurements of both parameters in vivo. STUDY DESIGN: Randomized controlled trial. Setting. Animal study. Subjects and Methods. After assessment of normacusis (0 minutes) using evoked auditory brainstem responses (ABRs), noise (106-dB sound pressure level [SPL]) was applied to both ears in 6 guinea pigs for 30 minutes while unexposed animals served as controls. In vivo fluorescence microscopy of the stria vascularis capillaries was performed after surgical exposure of 1 cochlea. ABR measurements were derived from the contralateral ear. RESULTS: After noise exposure, red blood cell velocity was reduced significantly by 24.3% (120 minutes) and further decreased to 44.5% at the end of the observation (210 minutes) in contrast to stable control measurements. Vessel diameters were not affected in both groups. A gradual decrease of segmental blood flow became significant (38.1%) after 150 minutes compared with controls. Hearing thresholds shifted significantly from 20.0 ± 5.5 dB SPL (0 minutes) to 32.5 ± 4.2 dB SPL (60 minutes) only in animals exposed to loud noise. CONCLUSION: With regard to novel treatments targeting the stria vascularis in NIHL, this standardized model allows us to analyze in detail cochlear microcirculation and hearing function in vivo.
Authors: Thomas Münzel; Mette Sørensen; Frank Schmidt; Erwin Schmidt; Sebastian Steven; Swenja Kröller-Schön; Andreas Daiber Journal: Antioxid Redox Signal Date: 2018-03-20 Impact factor: 8.401
Authors: Katie Frenis; Sanela Kalinovic; Benjamin P Ernst; Miroslava Kvandova; Ahmad Al Zuabi; Marin Kuntic; Matthias Oelze; Paul Stamm; Maria Teresa Bayo Jimenez; Agnieszka Kij; Karin Keppeler; Veronique Klein; Lea Strohm; Henning Ubbens; Steffen Daub; Omar Hahad; Swenja Kröller-Schön; Michael J Schmeisser; Stefan Chlopicki; Jonas Eckrich; Sebastian Strieth; Andreas Daiber; Sebastian Steven; Thomas Münzel Journal: Front Mol Biosci Date: 2022-01-31