Abstract

COMPARATIVE STUDY OF THE OTOPROTECTIVE EFFICACY OF VITAMIN-C AND N-ACETYLCYSTEINE AGAINST CISPLATIN-INDUCED OTOTOXICITY IN WISTAR RATS: AN INSIGHT INTO FREQUENCY-SPECIFIC MECHANISM

Olawale Olusoga Olubi*, Kofoworola Oluwaseyi Yusuf, Kosisochukwu Victory Arinze, Mary Oluwatobiloba Jacob, Adekunle Azeez Adebayo, Abdulfatai Olakunle Ojewale, Sunday Sokunle Soyemi, Simeon Olubukola Afolabi and Omoniyi Kayode Yemitan

ABSTRACT

The prevalence of Cisplatin-induced ototoxicity has attracted research interest. However, there is limited scientific data on the frequency-specific otoprotective effects of Vitamin C and N-acetylcysteine on Cisplatin-induced ototoxicity. This study assessed and evaluated the otoprotective impact of vitamin C and N-acetylcysteine on Cisplatin-induced ototoxicity. Thirty Wistar rats were randomly distributed into six study groups (n=5) after a baseline Distortion Product Otoacoustic Emission (DPOAE) was conducted before selecting the rats with normal hearing. The six groups had the following treatment regimen for 10 days. Group 1: Normal Saline (1 ml/kg/day), Group 2: Cisplatin (15 mg/kg/day), Group 3: Vitamin C (100 mg/kg/day) + Cisplatin (15 mg/kg/day), Group 4: vitamin C (200 mg/kg/day) + Cisplatin (15 mg/kg/day), Group 5: N-acetylcysteine (300 mg/kg/day) + Cisplatin (15 mg/kg/day), Group 6: Hydrocortisone (60 mg/kg/day) + Cisplatin (15 mg/kg/day). The final DPOAE was measured on the tenth day at 2 kHz, 3 kHz, 4 kHz, and 5 kHz, while the cochlea was collected for histological examination. There was a loss of functional hearing in the Cisplatin-only group, while the groups treated with Vitamin C or N-acetylcysteine showed significant elevations in DPOAE. Vitamin C produced lower DPOAE levels compared to N-acetylcysteine at frequencies of 2 kHz and 3 kHz, but not at higher frequencies. Vitamin C and N-acetylcysteine produced protective effects against Cisplatin-induced ototoxicity with N-acetylcysteine possessing higher protective effects when compared to the higher dose of Vitamin C at lower frequencies.

Keywords: Vitamin C, N-acetylcysteine, Ototoxicity, Cisplatin, Distortion Product Otoacoustic Emission (DPOAE).