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

Autor:	Zucki F; Universidade de São Paulo (USP), Faculdade de Odontologia de Bauru, Bauru, SP, Brazil. Electronic address: fernandazucki@hotmail.com., Morata TC; National Institute for Occupational Safety and Health (NIOSH), Atlanta, USA., Duarte JL; Universidade de São Paulo (USP), Faculdade de Odontologia de Bauru, Departamento de Fonoaudiologia, Bauru, SP, Brazil., Ferreira MCF; Universidade de São Paulo (USP), Faculdade de Odontologia de Bauru, Departamento de Fonoaudiologia, Bauru, SP, Brazil., Salgado MH; Universidade Estadual Paulista 'Júlio de Mesquita Filho' (UNESP), Departamento de Engenharia de Produção, Bauru, SP, Brazil., Alvarenga KF; Universidade de São Paulo (USP), Faculdade de Odontologia de Bauru, Departamento de Fonoaudiologia, Bauru, SP, Brazil.
Jazyk:	angličtina
Zdroj:	Brazilian journal of otorhinolaryngology [Braz J Otorhinolaryngol] 2018 Mar - Apr; Vol. 84 (2), pp. 150-158. Date of Electronic Publication: 2017 Jan 23.
DOI:	10.1016/j.bjorl.2016.12.004
Abstrakt:	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 400mg/L) and supplemented with ferrous sulfate (20mg/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<0.0001). Both concentrations of lead acetate affected the maturation state of the auditory system, being the maturation slower in the regions corresponding to portion of the auditory nerve (wave I) and cochlear nuclei (wave II). The ferrous sulfate supplementation reduced significantly the concentration of lead in blood and brainstem for the group exposed to the lowest concentration of lead (100mg/L), but not for the group exposed to the higher concentration (400mg/L). 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. (Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. All rights reserved.)
Databáze:	MEDLINE
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