Professor Ueyama Takehiko (Biosignal Research Center, Kobe University) and the inner ear research group (Kyoto Prefectural University of Medicine) have identified the cell types in the inner ear cochlea responsible for the production of superoxide (Nox3-expressing cells). They achieved this by using genetically modified mice that they developed. The researchers discovered that these superoxide-producing cells increase in number in response to aging, noise damage, and ototoxic drugs, thus causing age-related, noise-induced and drug-induced hearing loss. In addition, they were able to suppress the onset of these three types of acquired hearing loss in genetically modified mice with no Nox3 expression (Nox3 knockout).