An experimental drug can restore hearing in deaf mice by regenerating sound-sensitive cells in the inner ear.

Excessive noise permanently damages hair cells that conduct sound to the brain and are found in an inner-ear structure called the cochlea. A team led by Albert Edge at Harvard Medical School in Boston, Massachusetts, has identified a molecule that can convert other cochlear cells into hair cells. The compound, named LY411575, blocks a biochemical pathway called Notch, which normally prevents supporting cells in the cochlea from developing into hair cells. When applied to the ears of mice deafened by loud sounds, the molecule triggered the generation of new hair cells. By three months after this treatment, the rodents' hearing had been partly restored.

LY411575 would probably need to be delivered locally to the ear in humans to avoid side effects, the authors say.

Neuron 77, 58–69 (2013)