Protective Effects of Coadministration of NAC and CoQ10 Against Noise Induced Hearing Loss

Background Previous studies demonstrated partial attenuation of noise induced hearing loss (NIHL) by N-acetyl-L-cysteine (NAC) or CoQ₁₀ (ubiquinone). Objectives The present study investigates the protection effect of coadministration of NAC and CoQ₁₀ against NIHL. Methods In an experimental study in Iran in 2015, a total of 36 male Wistar rats (275 ± 25 g) were divided randomly based on the permuted block design into 6 experimental groups: (I) noise controls, (II) noise and NAC, (III) noise and CoQ₁₀, (IV) noise and CoQ₁₀ and NAC, (V) noise and saline (as vehicle of NAC) and (VI) noise and olive oil (as vehicle of CoQ₁₀). Antioxidants and vehicles were intraperitoneally injected once a day for two days prior to and 1 hour before 102 ± 0.5 dB white noise exposure 8 h/day in 10 executive days and two days after the noise exposure daily. Distortion product otoacoustic emissions were measured one day before and 1, 7 and 21 days after the exposure. Results The temporary hearing changes that occurred 1-day post exposure were not significantly different in all groups (P > 0.05). The total recovery (between 1 - 21 days after noise exposure) varied by a frequency increase between 1.08 - 19.10 in the noise group compared to 1.75 - 24.5 and 0.62 - 22.08 in animals treated with NAC and the combination of NAC and CoQ₁₀ respectively. The less permanent hearing impairment was observed in noise exposed animals treated with either NAC or both NAC and CoQ₁₀. Conclusions The effect of coadministration of NAC and CoQ₁₀ was neither additive nor synergic in protecting against NIHL.