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Wednesday, June 19, 2019

Reducing Brain Inflammation May Treat Tinnitus and Other Effects of Hearing Loss

A new study published in PLOS Biology showed that inflammation in the sound-processing region of the brain mediates ringing in the ears of mice that have noise-induced hearing loss. Shaowen Bao, PhD of the University of Arizona and the colleagues who conducted this research examined neuroinflammation in the auditory cortex of the brain following noise-induced hearing loss, and its role in tinnitus, in rodent models. Tinnitus, the perception of ringing in the ears, is a major factor when suffering from hearing loss, which affects about 500 million individuals.

The research found that noise-induced hearing loss is associated with increased levels of molecules called pro-inflammatory cytokines and the activation of non-neuronal cells called microglia in the primary cortex. Experiments in mice that suffer from noise-induced hearing loss showed that a cell-signaling molecule called tumor necrosis factor alpha (TNFα) mediates neuroinflammation, tinnitus, and synaptic imbalance. The study, which was published in PLOS Biology, also found that the pharmacological blockage of TNFα or the decrease of microglia prevented tinnitus in mice with noise-induced hearing loss. The authors of the study believe that neuroinflammation may be a therapeutic target for treating tinnitus and other hearing loss-related disorders.

"It is too early to generalize these findings from rodent models to human tinnitus, or from noise-induced tinnitus to the tinnitus of other etiologies," Bao told The Hearing Journal. "But we can begin to consider neuroinflammation as a potential risk factor for tinnitus."