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

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 110 dB sound at a frequency of 4 kHz for 2 h to simulate acoustic trauma. Group 1, group 2, group 3, and group 4 received 1 ml saline, 200 mg/kg curcumin, 350 mg/kg NAC, or 1 ml ethyl alcohol, respectively, intraperitoneally 30 min before and 24 and 48 h after acoustic trauma. Distortion product otoacoustic emissions (DPOAEs) were recorded before and after the acoustic trauma, and 72 h after drug administration. In group 2, signal-to-noise ratio (SNR) values in frequencies of 1000 Hz, 1500 Hz, and 4000 Hz 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 6000 Hz 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. © Association of Otolaryngologists of India 2020.