Schematic of neurogenesis study in perinatally arsenic-exposed mice.

<p>Female mice were given arsenic-treated water (50 ppb), made from sodium arsenate and ultra pure water, for seven days prior to mating. Dams drank arsenic-treated water (50 ppb) throughout pregnancy into the postnatal period. Offspring were weaned at PD23–25 and given tap water (∼5 ppb As) in standard cages. Four i.p. BrdU injections (50 mg/kg) were given over the course of 12 hours on PD34; animals were sacrificed on PD35 and proliferation of adult neurogenesis was assessed. For assessment of differentiation, a subset of animals was sacrificed four weeks later on PD63. Another cohort of animals was used for the enriched environment experiments. Brief, daily (2–4 hours) exposure to an enriched environment with a ladder, toys, housing, a running wheel, and other animals began on PD35. For proliferation assessment, animals were sacrificed five days later on PD40; for differentiation assessment, animals were sacrificed at PD63 with exposure to enrichment lasting one month. Another cohort of animals with and without exposure to enrichment was sacrificed at PD70 for mRNA assessment of neurogenesis-related genes.