The Protective Effect of Intratympanic Alpha Lipoic Acid on Cisplatin-Induced Ototoxicity on Rats

OBJECTIVE: The objective of this study is to investigate the effect of intratympanic alpha lipoic acid (alpha-LA) on cisplatin-induced ototoxicity by using distortion product otoacoustic emission (DPOAE). MATERIALS and METHODS: A total of 24 Wistar albino rats were randomly divided into three groups: group 1 received intraperitoneal (IP) saline + intratympanic (IT) saline as a control group for 4 days (n=8), group 2 received IP cisplatin (20 mg/kg) + IT saline (0.1-0.3 mL) for 4 days (n=8), and group 3 received IP cisplatin (20 mg/kg) + IT alpha-LA (25 mg/mL) for 4 days (n=8). DPOAEs were performed prior to the procedure and at the end of the experiment on day 5. RESULTS: Statistically significant DPOAE amplitude reductions were found in the group 2 at all frequencies (2-9 kHz) that demonstrate severe cisplatin ototoxicity (p<0.01). IT alpha-LA injection provided a protective effect against cisplatin-induced ototoxicity at 3.2, 3.8, 4.5, 5.4, 6.3, and 7.6 kHz frequencies (p<0.05). CONCLUSION: In our study IT alpha-LA showed a protective effect against cisplatin-induced ototoxicity in a large frequency range.