Induction of spontaneous otoacoustic emissions in chinchillas from carboplatin-induced inner hair cell loss.

Fifteen chinchillas were evaluated for spontaneous otoacoustic emissions (SOAEs) before and after administering carboplatin (126-200 mg/kg), an anti-neoplastic drug that selectively destroys inner hair cells (IHCs) in this species. SOAEs were absent from all animals prior to carboplatin treatment, but at 1 week post-treatment, 47% of the animals and 30% of the ears had developed SOAEs. SOAE frequencies were clustered between 5 and 10 kHz and SOAE intensity ranged from 10 to 32 dB SPL. All of the ears with SOAEs had IHC lesions exceeding 60% throughout most of the cochlea and two ears had outer hair cell lesions of 25-60% at a cochlear place associated with the frequency of the SOAE. Thus, high doses of carboplatin that cause IHC loss can be used to create an animal model with SOAEs.