Up-regulation of hypoxia-inducible factor-1 alpha by cobalt chloride prevents hearing loss in noise-exposed mice

Since hypoxia-inducible factor-1 alpha (HIF-1 alpha) is the key transcription factor that enables cells to survive in hypoxia, we have investigated whether an upregulation of HIF-1 alpha prevents the noise-induced hearing loss in BALB/c hybrid mice, which were intraperitoneally injected with CoCl(2) (a HIF-1 alpha inducer) and exposed to white band noise with 120 dB peak equivalent sound pressure level for 3h once daily for 3 days. In the CoCl(2) treatment group, HIF-1 alpha was found to be up-regulated in the cochlear tissues and the hearing loss was largely prevented. Histologically, the loss of sensory hair cells was also significantly lower in the CoCl(2) treatment group than the Control group. However, YC-1 (a HIF-1 alpha inhibitor) attenuated the preventive effect of CoCl(2) on the noise-induced hearing loss. These results suggest that HIF-1 alpha plays a crucial role in the prevention against noise trauma in the inner ear. (C) 2010 Elsevier B.V. All rights reserved.