Effect of high-dose cisplatin on auditory brainstem responses and otoacoustic emissions in laboratory animals

Objective: The role of transient evoked otoacoustic emissions (TEOAE) and d istortion product otoacoustic emissions (DPOAE) as early indicators of cisp latin-induced ototoxicity in three different rodent species-the guinea pig, the albino rat, and the fat sand rat (Psammomys obesus)-was investigated. In addition, an attempt was made to determine which of the three rodent spe cies is most susceptible to cisplatin-induced ototoxicity as measured by au ditory brainstem responses (ABR), TEOAE, and DPOAE. Background: There have been numerous clinical and experimental reports on c isplatin-induced ototoxicity, but to the authors' best knowledge, there has been no comparative report on the short-term effects of cisplatin on OAE m easured with commercially available equipment between different rodent spec ies. Methods: Cisplatin was systemically administered as a single high dose (12 mg/kg intraperitoneally) to all three species, and the ototoxic effects wer e measured before and 3 days after the injection of cisplatin in the same a nimals, using ABR, TEOAE, and DPOAE. Results: The ABR thresholds were significantly elevated in the guinea pigs and the albino rats but nor in the sand rats. Significant depression of TEO AE energy and DPOAE amplitude occurred only in the guinea pigs. The depress ion of the DPOAE was greater than that of the TEOAE. The guinea pigs showed the greatest degree of ototoxicity (depression of ABR and OAE). Conclusions: Among the three rodent species, the guinea pig has the potenti al to be used as a sensitive animal model in studies of cisplatin ototoxici ty. The study also showed that the recordings of TEOAE and DPOAE, in additi on to ABR, are sensitive techniques for the assessment of cisplatin-induced ototoxicity.