Investigation of the Effect of Allicin on Noise-Induced Hearing Loss in Rats

Background and Objectives: Noise-induced hearing loss (NIHL) is a major cause of sensorineural hearing loss. However, effective pharmacological treatments remain limited. The aim of this study was to investigate the therapeutic effects of allicin on NIHL in a rat model. Materials and Methods: Forty-two female Wistar albino rats were randomly divided into six groups (n= 7 per group): saline (SF), allicin, dimethyl sulfoxide (DMSO), noise+SF, noise+allicin+DMSO, and noise+DMSO. Noise exposure was performed using 4 kHz octave-band noise at a sound pressure level (SPL) of 120 dB for 4 hours. Allicin (20 mg/kg/day, intraperitoneally) was administered for 7 days following noise exposure. Auditory brainstem response (ABR) thresholds (dB SPL) were measured at 8, 12, 16, 20, and 32 kHz at baseline, 24 hours, and day 7. Histopathological evaluation of the cochlea was performed after euthanasia. Results: Noise exposure significantly increased ABR thresholds in all noise-exposed groups. On day 7, the noise+allicin+ DMSO group demonstrated significantly lower ABR thresholds at 16, 20, and 32 kHz compared with the noise+SF group and at 20 and 32 kHz compared with the noise+DMSO group (<i>p</i><0.05). No significant differences were observed at lower frequencies. Histopathological analysis showed a trend toward reduced cochlear damage in the allicin-treated group; however, the differences were not statistically significant. Conclusions: Allicin treatment improved high-frequency hearing thresholds in rats with NIHL. However, the absence of significant histopathological and mechanistic findings indicates that further molecular and region-specific studies are required.