title: Early chronic lead exposure reduces exploratory activity in young C57BL/6J mice.
abstract: Research has suggested that chronic low-level lead exposure diminishes neurocognitive function in children. Tests that are sensitive to behavioral effects at lowest levels of lead exposure are needed for the development of animal models. In this study we investigated the effects of chronic low-level lead exposure on exploratory activity (unbaited nose poke task), exploratory ambulation (open field task) and motor coordination (Rotarod task) in pre-adolescent mice. C57BL/6J pups were exposed to 0 ppm (controls), 30 ppm (low-dose) or 230 ppm (high-dose) lead acetate via dams' drinking water administered from birth to postnatal day 28, to achieve a range of blood lead levels (BLLs) from not detectable to 14.84 µg dl(-1) ). At postnatal day 28, mice completed behavioral testing and were killed (n = 61). BLLs were determined by inductively coupled plasma mass spectrometry. The effects of lead exposure on behavior were tested using generalized linear mixed model analyses with BLL, sex and the interaction as fixed effects, and litter as the random effect. BLL predicted decreased exploratory activity and no threshold of effect was apparent. As BLL increased, nose pokes decreased. The C57BL/6J mouse is a useful model for examining effects of early chronic low-level lead exposure on behavior. In the C57BL/6J mouse, the unbaited nose poke task is sensitive to the effects of early chronic low-level lead exposure. This is the first animal study to show behavioral effects in pre-adolescent lead-exposed mice with BLL below 5 µg dl(-1).
authors.affiliation: Border Biomedical Research Center, Toxicology Core, University of Texas, El Paso, TX, USA.|Department of Psychology, University of Texas, El Paso, TX, USA.
authors.forename: Mayra Gisel
authors.initials: MG
authors.lastname: Flores-Montoya
authors.affiliation: Border Biomedical Research Center, Toxicology Core, University of Texas, El Paso, TX, USA.|Department of Public Health Sciences, College of Health Sciences, University of Texas, El Paso, TX, USA.|Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Sobin
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects*; D005260:Female; D007854:Lead / Q000097:blood; D020264:Lead Poisoning, Nervous System, Childhood / Q000523:psychology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D045442:Rotarod Performance Test; D013054:Spectrophotometry, Atomic
chemical_list: D007854:Lead
keywords: cognition; developmental lead exposure; exploratory activity; mouse model; neurobehavioral toxicity