MITOCHONDRIAL THERAPEUTICS CAN ATTENUATE NOISE DAMAGE TO COCHLEA

Recent attempts to use mitochondria as a therapeutic agent have yielded promising results, with some reports suggesting their effectiveness. McCully et al. reported that autologous mitochondria injected into the heart muscle during cardiac surgery resulted in faster recovery compared to non-injection procedures. Since the first clinical trial began in ischemic heart disease , studies are also ongoing in Pearson syndrome, acute ischemic encephalopathy, and sepsis.
The auditory organ, which detects sound, constantly consumes a lot of energy, actively producing and using ATP. This means that mitochondria are constantly active. This study was conducted to make noise-induced hearing loss in animals and administer mitochondria before and after noise exposure to determine whether hearing was preserved. Twelve-week-old C57BL/6 mice were used, and exposed to 120 dB SPL white noise for 2 hours to induce noise-induced hearing loss. Mitochondria were injected into the tail vein of the mice (20 µg) before and after noise exposure. Hearing was measured using clicks and 8 kHz tone bursts to measure auditory brainstem response before noise exposure and on days 1, 4, 7, and 14 after exposure. After measuring hearing on the 14th day, cochleae were removed and immunohistochemical staining was performed. In the experimental group that received mitochondria, hearing thresholds showed better than control group. Immunostaining confirmed that hair cells in the cochlea were alive and well, which suggests that mitochondria administered before and after noise exposure can prevent and reduce noise damage.