Open AccessOtotoxicity in Rats Exposed to Ortho‐, Meta‐ and Para‐Xylene Vapours for 13 Weeks
Author(s) -
Gagnaire François,
Marignac Brigitte,
Langlais Cristina,
Bonnet Pierre
Publication year - 2001
Publication title -
pharmacology & toxicology
Language(s) - English
Resource type - Journals
eISSN - 1600-0773
pISSN - 0901-9928
DOI - 10.1111/j.1600-0773.2001.890102.x
Subject(s) - ototoxicity , outer hair cells , auditory brainstem response , organ of corti , xylene , inhalation , toxicity , inhalation exposure , brainstem , chemistry , hearing loss , medicine , anesthesia , audiology , cochlea , toluene , organic chemistry , chemotherapy , cisplatin
Male Sprague‐Dawley rats were exposed to ortho‐, meta‐ or para‐xylene by inhalation (450, 900 and 1800 p.p.m., 6 hr/day, 6 days/week for 13 weeks) and sacrificed for morphological investigations 8 weeks after the end of exposure. Brainstem auditory‐evoked responses were used to determine auditory thresholds at different frequencies. Among the three isomers studied, only para‐xylene produced moderate to severe ototoxicity in rats exposed at 900 and 1800 p.p.m. Increased auditory thresholds were observed at 2, 4, 8 and 16 kHz in rats exposed to 1800 p.p.m. para‐xylene. The auditory threshold shifts (35 to 38 dB) did not reverse after 8 weeks of recovery. Moderate and severe losses of outer hair cells of the organ of Corti occurred in animals exposed to 900 and 1800 p.p.m. para‐xylene respectively. Thus, the no observed effect level of para‐xylene was 450 p.p.m. based on the loss of outer hair cells observed by light and electron microscopy.