Developmental Exposure to a Commercial PBDE Mixture, DE-71: Neurobehavioral, Hormonal, and Reproductive Effects

Abstract

Developmental effects of polybrominated diphenyl ethers (PBDEs) have been suspected due to their structural similarities to polychlorinated biphenyls (PCBs). This study evaluated neurobehavioral, hormonal, and reproductive effects in rat offspring perinatally exposed to a widely used pentabrominated commercial mixture, DE-71. Pregnant Long-Evans rats were exposed to 0, 1.7, 10.2, or 30.6 mg/kg/day DE-71 in corn oil by oral gavage from gestational day 6 to weaning. DE-71 did not alter maternal or male offspring body weights. However, female offspring were smaller compared with controls from postnatal days (PNDs) 35-60. Although several neurobehavioral endpoints were assessed, the only statistically significant behavioral finding was a dose-by-age interaction in the number of rears in an open-field test. Developmental exposure to DE-71 caused severe hypothyroxinemia in the dams and early postnatal offspring. DE-71 also affected anogenital distance and preputial separation in male pups. Body weight gain over time, reproductive tissue weights, and serum testosterone concentrations at PND 60 were not altered. Mammary gland development of female offspring was significantly affected at PND 21. Congener-specific analysis of PBDEs indicated accumulation in all tissues examined. Highest PBDE concentrations were found in fat including milk, whereas blood had the lowest concentrations on a wet weight basis. PBDE concentrations were comparable among various brain regions. Thus, perinatal exposure to DE-71 leads to accumulation of PBDE congeners in various tissues crossing blood-placenta and blood-brain barriers, causing subtle changes in some parameters of neurobehavior and dramatic changes in circulating thyroid hormone levels, as well as changes in both male and female reproductive endpoints. Some of these effects are similar to those seen with PCBs, and the persistence of these changes requires further investigation.

Bioconcentration and metabolism of BDE-209 in the presence of titanium dioxide nanoparticles and impact on the thyroid endocrine system and neuronal development in zebrafish larvae

“…Alterations of locomotor behavior could be due to changes to the functions of genes and proteins in the central nervous system or by direct neurotoxic effects on neuronal cells (Chen et al, 2012b). PBDEs can cause neurobehavioral alterations in rodent models (Eriksson et al, 2002;Kodavanti et al, 2010). Recently, locomotor behavior was used as an approach to study the neurobehavioral effects of PBDEs in zebrafish (Chen et al, 2012b;Chou et al, 2010;He et al, 2011;Usenko et al, 2011).…”

Prenatal Transfer of Polybrominated Diphenyl Ethers (PBDEs) Results in Developmental Neurotoxicity in Zebrafish Larvae

“…Several previous studies have shown neurobehavioral alterations in rodent models upon exposure to PBDEs. 48,49 Recently, locomotor behavior approaches have also been performed to study the neurobehavioral effects of PBDEs in zebrafish. 29,50 Neurobehavior is an integrated response of many physiological and biochemical processes.…”

Parental Transfer of Polybrominated Diphenyl Ethers (PBDEs) and Thyroid Endocrine Disruption in Zebrafish

“…9 Exposure of the PBDE mixture DE-71 to zebrafish embryos/larvae has also been shown to result in a reduction of T4 in the larvae. 10 Like other lipophilic organic compounds, maternal transfer of several PBDEs has previously been observed in various species, such as frogs, 11 birds, 12,13 rats, 14 and humans. 15 Recently, maternal transfer of PBDEs to the offspring following parental exposure via feed was observed in zebrafish in laboratory experiments 16 and in the field.…”