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MID-FREQUENCY HEARING LOSS IN RATS FOLLOWING INHALATION EXPOSURE TO TRICHLOROETHYLENE: EVIDENCE FROM REFLEX MODIFICATION AUDIOMETRY
Citation:
Crofton, K. AND X. Zhao. MID-FREQUENCY HEARING LOSS IN RATS FOLLOWING INHALATION EXPOSURE TO TRICHLOROETHYLENE: EVIDENCE FROM REFLEX MODIFICATION AUDIOMETRY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/078 (NTIS PB94141504).
Description:
The present experiments were undertaken in order to characterize the hearing loss associated with 1,1,2-trichloroethylene (TCE) exposure. dult male LE rats were exposed to TCE via inhalation (whole body) for 6hr/day for 5 days. he concentration-effect function (0-4000 ppm) was determined three weeks post-exposure. nimals were tested for auditory thresholds to 4,8,16,24,32 and 40-kHz tones using reflex modification audiometry. n a separate experiment the time course of effects was determined by monitoring 16-kHz thresholds prior to, 1 hour following each the five exposure days, and 5 days, 1, 2, 4, 8 and 12 weeks post-exposure. t 14 weeks, these same animals were tested for thresholds to 0.5,1,2,4,8,16,24,32, and 40 kHz tones. esults indicate elevated thresholds (hearing loss) for the 4000 ppm group at 8 and 16 kHz of approximately 18 and 30 dB, respectively. ime-course data demonstrated a rapid onset, a 20dB loss at 16-kHz after the fifth exposure day, and a 40-dB loss by 2 weeks that persisted up to 14 weeks post-exposure. hese data demonstrate an atypical and persistent, mid-frequency hearing loss in rats following inhalation exposure to TCE.