Protective Effect of Nigella sativa Oil on Acoustic Trauma Induced Hearing Loss in Rats

Abstract

Acoustic trauma is a common reason for hearing loss. Different agents are used to prevent the harmful effect of acoustic trauma on hearing. The aim of this study was to evaluate the potential preventive effect of Nigella sativa (black cumin) oil in acoustic trauma. Our experimental study was conducted with 20 Sprague Downey female rats (mean age, 12 months; mean weight 250 g). All of the procedures were held under general anesthesia. Following otoscopic examinations, baseline-hearing thresholds were obtained using auditory brainstem responses (ABR). To create acoustic trauma, the rats were then exposed to white band noise of 4 kHz with an intensity level of 107 dB in a soundproof testing room. On Day 1 following acoustic trauma, hearing threshold measurements were repeated. The rats were divided into two groups as the study group (n: 10) and the controls (n: 10). 2 mL/kg/day of Nigella sativa oil was given to the rats in the study group orally. On Day 4 following acoustic trauma, ABR measurements were repeated again. There was no difference between the baseline hearing thresholds of the rats before acoustic trauma (P>0.005). After the acoustic trauma, hearing thresholds were increased and there was no significant statistically difference between the hearing thresholds of the study and control groups (P=0.979). At the 4th day following acoustic trauma, hearing thresholds of the rats in control group were found to be higher than those in the study group (P=0.03). Our results suggest that Nigella sativa oil has a protective effect against acoustic trauma in early period. This finding should be supported with additional experimental and clinical studies, especially to determine the optimal dose, duration and frequency of potential Nigella sativa oil therapy.