In utero exposure to low-dose 2,3',4,4',5-pentachlorobiphenyl (PCB 118) impairs male fertility and alters neurobehavior in rat offspring

Neurobehavior (motor activity and developmental reflexes) and male reproductive parameters were evaluated in rat offspring after in utero exposure to a low dose of PCB 118 comparable to human exposure levels. Sprague-Dawley dams were treated on gestation day 6 by gavage with a single dose of 375 microg PCB 118/kg body weight or peanut oil (control). The dose was calculated to be approximately 100-fold higher than that found in human breast milk. Postnatal reflexes, motor activity and male reproductive performance were evaluated in rat offspring after exposure to PCB 118. Evaluation of locomotor activity for five consecutive days during puberty (PND 70-74) revealed hyperactivity in offspring from PCB 118-exposed dams. In adult males (PND 170), clear effects on reproductive organs were observed in PCB-exposed animals which had smaller testes, epididymides and seminal vesicles (absolute and relative weights). Decreases in sperm and spermatid numbers and impairment of daily sperm production were also observed. Our results clearly demonstrate that low-dose exposure to PCB 118 alters neurobehavior and impairs adult male fertility in offspring. This is in contrast to the reported increases in sperm production and testis weight in rat after high dose PCB exposures. PCBs appear to possess variable dose-related effects and therefore low-dose studies are important to obtain a complete picture for human risk assessment.