Lead-induced hearing loss in rats and the protective effect of copper.

Lead is a common environmental pollutant which can induce various toxic effects to humans and/or animals. This work aimed to study the hearing loss in rats induced by lead and the protective effect of copper. The auditory brainstem response (ABR) was used to study the hearing loss in rats. The results showed that lead prolonged the latencies of wave I to V of ABRs of the rats but did not affect the interpeak latencies of waves I-III, III-V, and I-V, indicating that lead could cause hearing loss in rats by impairing the cochlea. After receiving copper, the quality and the wave latencies of the ABR of the rats were restored to a certain extent, indicating that copper played a protective role in lead-induced hearing impairment. The mechanisms were also proposed that lead could cause hearing loss in rats mainly through damaging the cochlea component, and copper might antagonize the toxicity of lead in three primary ways.