The ototoxicity of trichloroethylene : Extrapolation and relevance of high-concentration, short-duration animal exposure data.
Inhalation exposure to high concentrations of 1,1,2-trichloroethylene (TCE) has been shown to damage hearing in the mid-frequency range in the rat.
The present study directly evaluated the adequacy of high-concentration, short-term exposures to TCE for predicting the neurotoxicity produced by longer duration exposures.
Adult male Long-Evans rats (n=10-12 per group) were exposed to TCE via inhalation (whole body) in 1-m3 stainless steel flow-through chambers for 6 hr/day, 5 days/week.
The following exposures were used : 1 day (4000-8000 ppm), 1 week (1000-4000 ppm), 4 weeks (800-3200 ppm), and 13 weeks (800-3200 ppm).
Air-only exposed animals served as controls.
Auditory thresholds were determined for a 16-kHz tone 3-5 weeks after exposure using reflex modification audiometry.
Results replicated previous findings of a hearing loss at 16 kHz for all exposure durations.
The dB15 concentrations (concentration that increases thresholds by 15 dB) for 16-kHz thresholds were 6218,2992,2592, and 2160 ppm for the 1-day, 1-week, 4-week and 13-week exposures, respectively.
These data demonstrate that the ototoxicity of TCE was less than that predicted by a strict concentration X time relationship.
These data also demonstrate that simple models of extrapolation (i.e., C x t=k, Haber's Law) overestimate the potency of TCE when extrapolating from short-duration to longer-duration exposures. (...)
Mots-clés Pascal : Toxicité, Système nerveux pathologie, Oreille pathologie, Inhalation, Rat, Rodentia, Mammalia, Vertebrata, Animal, Dose forte, Court terme, Exposition professionnelle, Médecine travail, Solvant organique, Ethylène(trichloro)
Mots-clés Pascal anglais : Toxicity, Nervous system diseases, Ear disease, Inhalation, Rat, Rodentia, Mammalia, Vertebrata, Animal, High dose, Short term, Occupational exposure, Occupational medicine, Organic solvent, Ethylene(trichloro)
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 97-0460817
Code Inist : 002B03L04. Création : 03/02/1998.