The International Tinnitus Journal

Protecting the Inner Ear from Acoustic Trauma

Calcium activated proteases, or calpains, play an important role in neurodegeneration. In some cases, neural degeneration can be significantly reduced by leupeptin, a potent calpain inhibitor. To determine if leupeptin could protect against noise-induced bearing loss and hair cell loss, we infused leupeptin into scala tympani of one cocblea before, during and after a 14-day exposure to a 100 dB SPL, octave band noise centered at 4.0 kHz. Hearing loss, assessed with the auditory evoked response, was less in the leupeptin-treated ear than in the control ear during the early stage of recovery from acoustic trauma. In addition, hair cell loss in the leupeptin-treated ear was significantly less than in the control ear. These preliminary results suggest tbat leupeptin may protect against noise-induced hearing loss.