Assessment of ototoxicity of tea tree oil in a chinchilla animal model

Objective The aim of the present study is to examine the effects of tea tree oil on hearing function and cochlear morphology after intratympanic administration in a chinchilla animal model. Methods Nine chinchillas received intratympanic injection of 3% tea tree oil dissolved in olive oil in one ear, whereas the contralateral control ear received olive oil only. Outcome measures included auditory brainstem responses conducted before treatment and at 10 days and 30 days following the injection. Post-mortem cochlear morphology was assessed using scanning electron microscopy. Results At 10 and 30 days following the injection, there was no significant change in auditory brain response thresholds at 8, 16, 20 or 25 kHz. Scanning electron microscopy imaging showed no damage to auditory hair cells. Conclusion Tea tree oil (3%) does not appear to be ototoxic in a chinchilla animal model. Future preclinical and clinical studies are required to establish the effectiveness of TTO in treating otitis.