TEOAE monitoring of Cisplatin induced ototoxicity in guinea pigs: the protective effect of vitamin B treatment

Objective: To evaluate Cisplatin (CP) induced ototoxicity and the effects o f vitamin B treatment on ototoxicity in guinea pigs by using the Transient Evoked Otoacoustic Emission (TEOAE) technique. Methods: Eleven guinea pigs were divided into two groups and they were tested by TEOAE before and after the experiment. A TEOAE response was regarded as positive when all of the following criteria were met: 1. The mean amplitude of the cochlear response in dB pe SPL should be greater than that of the noise in the external audi tory canal; 2. The reproducibility rate of the response should be greater t han 50%; 3. The stimulus stability rate should be greater than 65%; 4. The signal to noise ratio of the response in 1, 2, 3, 4 and 5 kHz band frequenc ies should be greater than 3 dB pe SPL in at least two bands. The first gro up included five animals that had only CP injections. Six animals in the se cond group received additional 0.2 ml/kg combined vitamin B preparations fo r 7 consecutive days. Thereafter, the right and left ears of all animals in both groups were tested by TEOAE. Results: TEOAE responses recorded from 2 2 ears of 11 guinea pigs before drug administrations showed that the respon ses with maximum amplitude were originated from the mid-frequency legion. P ositive TEOAE responses were significantly reduced after CP administrations in both groups when compared with their respective pretreatment results (P < 0.01). However, vitamin B injections, in addition to a single large dose of CP, resulted in significantly better TEOAE responses than those obtaine d after only CP injections (P < 0.05). Conclusions: The routine use of TEOA E monitoring is recommended in clinical CP treatment protocols for the earl y detection and follow up of ototoxicity. Also, prospective clinical trials are needed in order to validate the protective effects of vitamin B treatm ent against ototoxicity. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.