Pesticide metabolite 3, 5, 6-trichloro-2-pyridinol causes massive damage to the cochlea resulting in hearing loss in adult mice

Pesticides are a group of extensively used man-made chemicals with high toxicity and strong residues, which are closely related to hearing health. Pesticide metabolite 3, 5, 6-Trichloro-2-pyridinol (TCP) exposure leads to neurotoxicity and auditory cell toxicity. However, whether TCP causes damage to hearing in adult mice is not clear. In this study, adult male C57BL/6 mice continuously exposed to TCP for 21 days showed a dose-dependent elevation of hearing threshold. Outer hair cells and spiral neuron cells were lost in a dose-dependent manner. Type I and V of spiral ligament were severely shrunk and stria vascularis were thinned in mice after 50 and 150 mg/kg TCP exposure. Similarly, ROS levels in the cochlea were significantly increased whereas the activities of anti-oxidation enzymes were decreased after TCP exposure. The expression level of Na