EN
Hes l, a hairy and enhancer of split homolog, negatively regulates inner ear hair cell differentiation. The main objective of this study was to investigate the status of the Hes l gene in the noise-damaged cochlea in relation to the degree of noise-induced hearing loss (NIHL). Adult albino guinea pigs were exposed to white-band noise (115 dB sound pressure level). Noise exposure for either 1 or hours induced significant elevations of threshold in auditory brainstem response (ABR) compared with unexposed controls. Succinate dehydrogenase staining showed that white-band noise exposure caused significant outer hair cell losses. In addition, we found significant up-regulations of cochlear Hesl mRNA and protein expressions following acoustic trauma, and Hesl mRNA expression was positively correlated with NIHL. These findings suggest that up-regulation of Hes l expression in response to noise exposure may be one of the underlying mechanisms of NIHL.