Friend or foe? Effect of oral resveratrol on cisplatin ototoxicity.

Objectives/hypothesis: Our objectives were to study effects of orally administered resveratrol (RV) against cisplatin (CDDP) ototoxicity in different doses and to investigate ultrastructural changes in the cochlea and brainstem.

Study Design: In vivo study using an animal model.

Methods: Thirty-two male Wistar albino rats were divided into six groups. Baseline distortion product otoacoustic emissions (DPOAEs) and auditory brainstem response (ABR) measurements were made. In groups I, II, and III, only saline, RV, and CDDP were given, respectively. Group IV, V, and VI animals were administered 10 mg/kg/day, 1 mg/kg/day, and 0.1 mg/kg/day of RV for 10 days, respectively, before 16 mg/kg CDDP injections were administered on day 11. All animals were sacrificed after repeated DPOAEs and ABR measurements were made on day 14. Cochleas of animals were investigated with transmission electron microscopy. Apoptosis were investigated with caspase-3 activity and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method in the brainstem.

Results: In groups IV and V, DPOAEs and ABR findings revealed that oral administration of RV 10 mg/kg/day and 1 mg/kg/day doses before CDDP injection enhanced ototoxicity. In group VI, electomicroscopy revealed better ultrastructural findings than in the cisplatin group; however, these changes were not reflected in the audiological findings accordingly.

Conclusions: Our results implied that there were noticeable differences between different oral RV doses used for cisplatin ototoxicity. Especially in higher doses, RV was observed to enhance cisplatin ototoxicity.