title: Increase in accumulation of polychlorinated biphenyls in offspring mouse brain via maternal coexposure to methylmercury and polychlorinated biphenyls.
abstract: Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are environmentally persistent neurodevelopmental toxicants. In Japan, the most common source of human exposure is the consumption of contaminated fish and seafood. We investigated the accumulation of MeHg and PCBs in the brains of dams and offspring mice maternally exposed to MeHg and/or PCBs. Pregnant mice (C57BL/6Cr) were assigned to one of four exposure groups: control, MeHg alone (MeHg in diet at 5 mg/kg as Hg), PCB alone (Aroclor1254 by gavage at the dose of 18 mg/kg body weight/3 days) and MeHg+PCB. Levels of MeHg and PCBs were measured in the whole brains of dams and offspring mice on postnatal day 21 (PND21) and at 9 weeks of age. Total mercury, MeHg and PCB congener concentrations were determined by CVAAS, GC-ECD and HRGC/HRMS, respectively. For the mercury concentrations, there were no significant differences between MeHg alone and MeHg+PCB except for pups at 9 weeks. The maternal PCB levels were not significantly different between MeHg+PCB and PCB alone. In pup brain on PND21, MeHg+PCB resulted in a significantly higher PCB level than PCB alone. Although the levels of lightly chlorinated (= 4CBs) homologues were lower for MeHg+PCB than for PCB alone, those of highly chlorinated (>= 5CBs) homologues were significantly higher on PND21 for MeHg+PCB. The PCB composition in dams and pups shifted to higher chlorinated homologues compared with the composition of administered Aroclor1254. For these reasons, further detailed studies are necessary to clarify the interactional effects of PCB metabolism after coexposure to MeHg and PCBs.
authors.affiliation: Environmental Health Sciences, Tohoku University Graduate School of Medicine.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Iwai-Shimada
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakamura
authors.forename: Norio
authors.initials: N
authors.lastname: Sugawara
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kurokawa
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Nakai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Satoh
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D020111:Chlorodiphenyl (54% Chlorine) / Q000737:chemistry / Q000378:metabolism; D004347:Drug Interactions; D005260:Female; D006801:Humans; D018811:Maternal Exposure; D008431:Maternal-Fetal Exchange; D008767:Methylmercury Compounds / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000378:metabolism*; D011247:Pregnancy; D013329:Structure-Activity Relationship
chemical_list: D008767:Methylmercury Compounds; D020111:Chlorodiphenyl (54% Chlorine); D011078:Polychlorinated Biphenyls