The effects of coenzyme q10 in the prevention and treatment of age-related hearing loss

Age-related hearing loss is characterized by gradual, progressive sensorineural hearing loss and deterioration of sound localization and currently no effective treatment is available targeting this issue. The aim of this study is to evaluate the effects of CoQ10 in the prevention and treatment of age-related hearing loss. For this purpose, 32 C57BL/6 mice were assigned into four groups as follows; control, sham control, early and late treatment. Treatment was started at three months of age in the early treatment group while at sixth month in the late treatment group. For detection of the hearing loss, ABR test was performed once every three months. At the end of the study period, the cochleae of the animals were harvested and iNOS, COX-2, NF-κB, Bcl-2, Bcl-xL, Bax and Bak levels were analyzed with Real-Time PCR. In the ABR's performed at the end of the study, hearing thresholds of the mice in early treatment group were better than other groups (p<0.001). Hearing levels were also better in late treatment group, compared to control groups, but the difference was not statistically significant (p>0.05). When the threshold shifts were analysed, the shift in early treatment group was significantly lower at all frequencies, when compared to control groups (p<0.001). Threshold shifts of early and late treatment groups were ranged between 11.875 dB and 23.125 dB. While this difference was not significant in 4 kHz (p<0.05), it was significantly lower in 8, 12, and 16 kHz (p<0.001). mRNA expression levels of pro-apoptotic genes Bax and Bak were lower (p<0.05), anti-apoptotic genes Bcl-2, Bcl-xL were higher (p<0.05) and NF-κB, COX-2 and iNOS genes that play a role in inflammation were lower (p<0.05), in the early treatment group. These results suggest that, CoQ10 is effective in prevention of age-related hearing loss, especially when started before the onset of hearing loss.