The maturation state of the auditory nerve and brainstem in rats exposed to lead acetate and supplemented with ferrous sulfate

Abstract Introduction The literature has reported the association between lead and auditory effects, based on clinical and experimental studies. However, there is no consensus regarding the effects of lead in the auditory system, or its correlation with the concentration of the metal in the blood. Objective To investigate the maturation state of the auditory system, specifically the auditory nerve and brainstem, in rats exposed to lead acetate and supplemented with ferrous sulfate. Methods 30 weanling male rats ( Rattus norvegicus , Wistar) were distributed into six groups of five animals each and exposed to one of two concentrations of lead acetate (100 or 400 mg/L) and supplemented with ferrous sulfate (20 mg/kg). The maturation state of the auditory nerve and brainstem was analyzed using Brainstem Auditory Evoked Potential before and after lead exposure. The concentration of lead in blood and brainstem was analyzed using Inductively Coupled Plasma-Mass Spectrometry. Results We verified that the concentration of Pb in blood and in brainstem presented a high correlation ( r  = 0.951; p Conclusion This study indicate that the lead acetate can have deleterious effects on the maturation of the auditory nerve and brainstem (cochlear nucleus region), as detected by the Brainstem Auditory Evoked Potentials, and the ferrous sulphate can partially amend this effect.