Differential susceptibility of rats and guinea pigs to the ototoxic effects of ethyl benzene

• Published in: Neurotoxicology and teratology Vol. 24; no. 4; pp. 503 - 510
• Main Authors: Cappaert, Natalie L.M, Klis, Sjaak F.L, Muijser, Hans, Kulig, Beverly M, Ravensberg, Luco C, Smoorenburg, Guido F
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-07-2002; Elsevier Science
• Subjects: Acoustic Stimulation; Animals; Audiometry, Evoked Response; Benzene Derivatives - blood; Benzene Derivatives - toxicity; Biological and medical sciences; Chemical and industrial products toxicology. Toxic occupational diseases; Chromatography, Gas; Cochlea - pathology; Electrocochleography; Ethyl benzene; Evoked Potentials, Auditory - drug effects; Evoked Potentials, Auditory - genetics; Female; Genetic Predisposition to Disease; Guinea pig; Guinea Pigs; Medical sciences; Ototoxicity; Outer hair cell; Rat; Rats; Rats, Inbred Strains; Species Specificity; Toxicology; Various organic compounds; Guinea pig; Rat; Electrocochleography; Outer hair cell; Ethyl benzene; Ototoxicity; Ear disease; Toxicity; Interspecific comparison; Rodentia; Auditory disorder; Inhalation; Vertebrata; Ethylbenzene; Mammalia; Animal; Cochlea; ENT disease
• ISSN: 0892-0362; 1872-9738
• DOI: 10.1016/S0892-0362(02)00208-8

The present study was designed to compare the ototoxic effects of volatile ethyl benzene in guinea pigs and rats. Rats showed deteriorated auditory thresholds in the mid-frequency range, based on electrocochleography, after 550-ppm ethyl benzene (8 h/day, 5 days). Outer hair cell (OHC) loss was found in the corresponding cochlear regions. In contrast, guinea pigs showed no threshold shifts and no OHC loss after exposure to much higher ethyl benzene levels (2500 ppm, 6 h/day, 5 days). Subsequently, a limited study (four rats and four guinea pigs) was performed in an attempt to understand these differences in susceptibility. Ethyl benzene concentration in blood was determined in both species after exposure to 500-ppm ethyl benzene (8 h/day, 3 days). At the end of the first day, blood of the rats contained 23.2±0.8-μg/ml ethyl benzene, whereas the concentration in guinea pig blood was 2.8±0.1 μg/ml. After 3 days, the concentration in both species decreased with respect to the first day, but the ethyl benzene concentration in rat blood was still 4.3 times higher than that in guinea pig blood. Thus, the difference in susceptibility between the species may be related to the ethyl benzene concentration in blood.