Accumulation of hypoxia-inducible factor-1α in mouse inner ear by noise stimulation

Exposure of mice to a 120 dB SPL broad band click sound for 3 h per day induced expression of hypoxia-inducible factor-1alpha (HIF-1alpha) in the organ of Corti, lateral wall tissue and spiral ganglion cells. In the organ of Corti, HIF-1alpha was expressed in inner and outer hair cells, pillar cells and Deiters' cells, but not in Hensen's cells or the tectorial, Reissner's or basement membrane. HIF-1alpha expression was definitely increased in mice with a permanent threshold shift, where the hearing level did not recover, even after 4 weeks. These results suggest that noise may induce tissue hypoxia in the inner ear and that the further study on the role of HIF-1alpha will be needed.