The protective effect of Ginkgo biloba extract against experimental cisplatin ototoxicity: animal research using distortion product otoacoustic emissions

Abstract

Cisplatin, an effective therapeutic agent for various human cancers, has dose-limiting side effects of ototoxicity and nephrotoxicity. Cisplatin ototoxicity is thought to result from increased amounts of toxic free radicals or cell membrane changes leading to increased intracellular calcium content. Ginkgo biloba extract prevents lipid peroxidation, decreases intracellular free oxygen radical levels, regulates the cell membrane calcium transport mechanism and prevents cell death. This study aimed to investigate the protective effect of Ginkgo biloba extract against cisplatin-induced ototoxicity in rats. Twenty Wistar albino rats with normal hearing (confirmed by distortion product otoacoustic emission testing prior to cisplatin application) were randomly allocated to two groups. Both groups received a single intraperitoneal dose of cisplatin (12 mg/kg). Group two also received daily intraperitoneal doses of Ginkgo biloba extract (100 mg/kg) for 10 days. Distortion product otoacoustic emission measurements were repeated on days 10 and 17 and signal-to-noise ratios were compared. Compared with group one, group two had significantly better distortion product otoacoustic emission results at 3, 4, 6 and 8 kHz on days 10 and 17. These findings suggest that Ginkgo biloba extract protects the inner ear against cisplatin-induced ototoxicity.