Congener-specific disposition of chiral polychlorinated biphenyls in lactating mice and their offspring: Implications for PCB developmental neurotoxicity

Izabela Kania-Korwel, Tracy Lukasiewicz, Christopher D. Barnhart, Marianna Stamou, Haeun Chung, Kevin M. Kelly, Stelvio Bandiera, Pamela J Lein, Hans Joachim Lehmler

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Abstract

Chiral polychlorinated biphenyl (PCB) congeners have been implicated by laboratory and epidemiological studies in PCB developmental neurotoxicity. These congeners are metabolized by cytochrome P450 (P450) enzymes to potentially neurotoxic hydroxylated metabolites (OH-PCBs). The present study explores the enantioselective disposition and toxicity of 2 environmentally relevant, neurotoxic PCB congeners and their OH-PCB metabolites in lactating mice and their offspring following dietary exposure of the dam. Female C57BL/6N mice (8-weeks old) were fed daily, beginning 2 weeks prior to conception and continuing throughout gestation and lactation, with 3.1 mmol/kg bw/d of racemic 2,20,3,50,6- pentachlorobiphenyl (PCB 95) or 2,20,3,30,6,60-hexachlorobiphenyl (PCB 136) in peanut butter; controls received vehicle (peanut oil) in peanut butter. PCB 95 levels were higher than PCB 136 levels in both dams and pups, consistent with the more rapid metabolism of PCB 136 compared with PCB 95. In pups and dams, both congeners were enriched for the enantiomer eluting second on enantioselective gas chromatography columns. OH-PCB profiles in lactating mice and their offspring were complex and varied according to congener, tissue and age. Developmental exposure to PCB 95 versus PCB 136 differentially affected the expression of P450 enzymes as well as neural plasticity (arc and ppp1r9b) and thyroid hormone-responsive genes (nrgn and mbp). The results suggest that the enantioselective metabolism of PCBs to OH-PCBs may influence neurotoxic outcomes following developmental exposures, a hypothesis that warrants further investigation.

Original languageEnglish (US)
Article numberkfx071
Pages (from-to)101-115
Number of pages15
JournalToxicological Sciences
Volume158
Issue number1
DOIs
StatePublished - Jul 1 2017

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Keywords

  • Atropisomer
  • Chiral
  • Cytochrome P450 enzymes
  • Metabolites
  • Persistent organic pollutants
  • Plasticity
  • Polychlorinated biphenyls

ASJC Scopus subject areas

  • Toxicology

Cite this

Kania-Korwel, I., Lukasiewicz, T., Barnhart, C. D., Stamou, M., Chung, H., Kelly, K. M., Bandiera, S., Lein, P. J., & Lehmler, H. J. (2017). Congener-specific disposition of chiral polychlorinated biphenyls in lactating mice and their offspring: Implications for PCB developmental neurotoxicity. Toxicological Sciences, 158(1), 101-115. [kfx071]. https://doi.org/10.1093/toxsci/kfx071