Acute postnatal exposure to brominated diphenylether 47 delays neuromotor ontogeny and alters motor activity in mice

Polybrominated diphenyl ethers (PBDEs) are widely used commercial flame retardants that are accumulating in the environment. PBDEs may interfere with the development of key biological systems, thus leaving children vulnerable to functional impairments in adulthood. There is a growing literature of animal studies that show subtle changes in motor and cognitive function following acute or repeated perinatal exposure to PBDEs. 2,2′,4,4′-Brominated diphenyl ether (BDE 47), a very stable PBDE congener, has been shown to accumulate in humans, perhaps as a breakdown product of other PBDEs. The current study examined developmental milestones in male C57BL/6 mice exposed to a single oral dose of BDE 47 (0, 1, 10, or 30 mg/kg) on postnatal day (PND) 10. Behavioral endpoints assessing sensory and motor maturation were examined on PNDs 12, 14, 16, 18, 32, and 88. Motor activity was also examined at 2 and 4 months in a separate group of mice. BDE 47 exposure (particularly the highest dose) significantly increased body weight on PND 47 and thereafter. There was altered ontogeny in a few measures of neuromotor development; however, other developmental milestones and sensory responses were not altered. Motor activity was altered at both 2 and 4 months, with BDE 47-treated mice (all dose groups) displaying pronounced hyperactivity at 4 months. These data indicate that acute exposure to BDE 47 during postnatal development may produce subtle changes in the development of neuromotor systems that may alter adult behavior.