Effect of intratympanic dexamethasone administration on cisplatin-induced ototoxicity in adult guinea pigs

Abstract Objective To evaluate the effect and safety of intratympanic dexamethasone administration on cisplatin-induced ototoxicity in adult male guinea pigs and to assess the differences between early and late protection from this ototoxicity. Methods Forty eight adult male guinea pigs were divided as follows: group I served as control group. Group II was subjected to intratympanic saline (subgroup IIa) or dexamethasone (subgroup IIb) injection. Group III was intraperitoneally injected with cisplatin. Groups IV and V were subjected first to intratympanic dexamethasone administration in both ears for 5 days starting 1 day and 1 h – respectively – before cisplatin intraperitoneal injection. Results Dexamethasone intratympanic injection revealed similar functional and structural results compared with control. Cisplatin intraperitoneal injection resulted in a profound cochlear functional and structural damage in group III. Non-significant otoprotection resulted from intratympanic dexamethasone administration one day before cisplatin. Intratympanic dexamethasone injection 1 h before cisplatin treatment resulted in a significant preservation of the functional and structural properties of the cochlea. Conclusion Intratympanic dexamethasone administration is a safe, easy and efficient way to protect from cisplatin ototoxicity especially when administered 1 h before cisplatin treatment.