Protective Effects of Curcumin and N-Acetyl Cysteine Against Noise-Induced Sensorineural Hearing Loss: An Experimental Study.

Abstract

We investigated the effectiveness of N-acetyl cysteine (NAC) and curcumin, which have known antioxidant and anti-inflammatory effects, in reducing acoustic trauma. We randomly divided 40 adult male rats into four groups: a control group (group 1), a curcumin group (group 2), a NAC group (group 3), and an ethyl alcohol group (group 4). The rats were exposed to 110dB sound at a frequency of 4kHz for 2h to simulate acoustic trauma. Group 1, group 2, group 3, and group 4received 1ml saline, 200mg/kg curcumin, 350mg/kg NAC, or 1ml ethyl alcohol, respectively, intraperitoneally 30min before and 24 and 48h after acoustic trauma. Distortion product otoacoustic emissions (DPOAEs) were recorded before and after the acoustic trauma, and 72h after drug administration. In group 2, signal-to-noise ratio (SNR) values in frequencies of 1000Hz, 1500Hz, and 4000Hz decreased in the second measurements when compared to the first, and showed improvements in the third measurements in comparison to the second ones. In group 3, SNR values decreased in the second measurements, but only the values at 6000Hz were found to be statistically significant (p = 0.007). The values in the third measurements were statistically significant when compared to the second ones. There was a statistically significant difference in the third measurements in both groups 2 and 3, possibly due to curcumin and NAC treatment. This study showed that curcumin and NAC may be effective against noise-induced hearing loss.