Document Type : Research articles


1 Department of Occupational Health Engineering, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran

2 Department of Occupational Health, Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, IR Iran


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.