Low-frequency hearing loss following perinatal exposure to 3,3 ',4,4 ',5-pentachlorobiphenyl (PCB 126) in rats

Previous research has demonstrated the sensitivity of the developing rat to the ototoxic effects of exposure to Aroclor 1254. In this study we assesse d the effects of developmental exposure to an individual PCB congener (3,3' ,4,4',5-pentachlorobiphenyl; PCB 126) on auditory function. Nulliparous Lon g Evans rats received either 0, 0.25, or 1.0 mu g/kg/day (5 days/week) for 35 days prior to breeding and throughout gestation and lactation. Auditory thresholds for 0.5-, 1-, 4-, 8-, 16-, 32-, and 40-kHz tones were assessed i n offspring on postnatal days (PND) 76-90. Perinatal maternal PCB 126 expos ure caused low-frequency hearing deficits. Elevated auditory thresh olds oc curred in the 1.0 mu g/kg/day treated group for 0.5- and 1-kHz tones, where as thresholds were not significantly affected at any higher frequencies. Th ese results are important in that the data implicate, at least partially, t he coplanar PCBs in the developmental ototoxicity induced by Aroclor 1254. Published by Elsevier Science Inc.