Scientists Discover Compound to Prevent Noise-Related Hearing Loss

We are constantly flooded by sounds in our modern world. Music in stores, vehicles and other loud noises degrade our hearing over the years. Now, scientists have discovered exactly what parts of our ears are damaged and how--and may have found a compound that could prevent this noise-related damage.

The compound in question is pigment epithelium-derived factor (PEDF). This protein is found in vertebrates and is currently being researched for treatment of heart disease and cancer. Yet scientists believed that this compound could also help prevent hearing loss.

"Noise-induced hearing loss, with accompanying tinnitus and sound hypersensitivity is a common conditions which leads to communication problems and social isolation," said Xiaorui Shi, one of the researchers, in a news release. "The goal of our study is to understanding the molecular mechanisms well enough to mitigate damage from exposure to loud sound."

In order to better understand how sound can impact our hearing, the researchers examined three groups of six- to eight-week-old mice. These groups consisted of one control group, a group exposed to broadband noise at 120 decibels for three hours a day for two days and a group given single-dose injections of PEDF prior to being exposed to the same amount of noise as the second group.

So what did they find? It turns out that the cells that secrete PEDF in control animals showed a characteristic branched morphology, with the cells arranging in a self-avoidance pattern. This provided good coverage of the capillary wall. The morphology of the same cells in the animals exposed to wide-band noise, though, showed clear differences; noise exposure caused changes in melanocytes located in the inner ear.

"Hearing loss over time robs people of their quality of life," said Gerald Weissmann, Editor-in-Chief of the FASEB Journal, in a news release. "It's easy to say that we should avoid loud noises, but in reality, this is not always possible. Front-line soldiers or first responders do not have time to worry about the long-term effects of loud noise when they are giving their all. If, however, a drug could be developed to minimize the negative effects of loud noises, it would benefit one and all."

The new findings could indeed eventually lead to the creation of a drug that could prevent noise-related hearing loss. PEDF seems to be promising, though more research will need to be conducted before scientists begin development.

The findings are published in The FASEB Journal.