Richard Smith, M.D. research Professor in Otolaryngology at University of Iowa said, "We gave a genetically-deafened mouse interfering RNA that specifically prevents a gene from being expressed that would otherwise cause deafness. By preventing its expression, we prevented the deafness. Even though this is in the early stages, it is really exciting because it points to other options for people who have hearing loss other than hearing aids or cochlear implants."

The way that the hearing loss is prevented is with a technique called RNA interference (RNAi). Many of the most common causes of genetic deafness will not be helped by this method of blocking the gene causing the damage. The kind of genetic hearing loss that possibly could be prevented would ones that have a dominant negative genetic function.

The mice had a mutated gene that causes deafness in humans put into the inner ear. The mice were measured with a hearing test similar to newborn babies at hospitals. The mice achieved a moderate hearing loss. The next step the hearing loss gene was put into mice’s ears along with the interfering RNA, which was designed to overpower the mutant gene. The results showed that the treated mice were able to hear.

The way the RNAi was delivered to the mice in this study would be easy to apply for therapy in humans. A small piece of foam soaked up the RNA and was placed against one opening of the mice’s inner ear. The membrane being slightly permeable was enough to allow the RNA to enter the inner ear cells.

Future studies will be conducted on mice before humans will be evaluated for this therapy. The researchers will study to see if the RNAi treatment will work on a mouse that has been deaf for an extended period of time.

By Nicole Wilson