Therapeutic efficacy of Ginkgo biloba for early-period noise-induced hearing loss: An experimental animal study

Objective: This study aimed to evaluate the effect of Ginkgo biloba extract (EGb 761) on noise induced hearing loss (NIHL) by measuring audiological and biochemical parameters. Materials and methods: Thirty-two female rats were divided into four groups (NIHL, EGb 761, NIHL + EGb 761 and control) comprising eight rats each. Groups 1 and 3 were exposed to white noise of a 100 dB sound pressure level (SPL) for 8 h, while rats in groups 2 and 3 were administered 100 mg/kg/day EGb 761 for 21 days after noise exposure. Distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) tests were performed in all groups before noise exposure and on days 1, 7, 14 and 21 after noise exposure. Intracardiac blood samples were taken on day 21 for assessment of biochemical parameters. Results: In group 1, a significant increase was seen in audiological measurements on days 1, 7, 14 and 21 after noise exposure. In group 3, the increased DPOAE and ABR threshold decreased significantly on day 14. The total oxidant status (TOS) value was significantly higher in group 1 than in the other groups. The total antioxidant status (TAS) value was significantly higher in group 2 than in group 1. The DNA damage value was significantly higher in group 1 than in the other groups. Conclusion: This study showed that EGb 761 is effective for treating NIHL during the early period. (C) 2016 Elsevier Inc. All rights reserved.