Maternal bisphenol A oral dosing relates to the acceleration of neurogenesis in the developing neocortex of mouse fetuses

Bisphenol A (BPA), an endocrine-disruptor, is widely used in the production of plastics and resins. Human perinatal exposure to this chemical has been proposed to be a potential risk to public health. Animal studies indicate that postnatal exposure to BPA may affect neocortex development in embryos by accelerated neurogenesis and causing neuronal migration defects. The detailed phenotypes and pathogenetic mechanisms, especially with regard to the proliferation and differentiation of neural stem/progenitor cells, however, have not been clarified. C57BL/6J pregnant mice were orally administered BPA at 200 μg/kg from embryonic day (E) 8.5 to 13.5, and the fetuses were observed histologically at E14.5. To clarify the histological changes, especially in terms of neurogenesis, proliferation and cell cycle, we performed histological analysis using specific markers of neurons/neural stem cells and cell cycle-specific labeling experiments using thymidine-analog substances. Cortical plate was hyperplastic and the number of neural stem/progenitor cells was decreased after the exposure to BPA. In particular, the maternal BPA oral dosing related to the effects on intermediate progenitor cells (IPCs, neural progenitor cells) in the subventricular zone (SVZ) of dorsal telencephalon. Exposure to BPA associated the promotion of the cell cycle exit in radial glial cells (RGCs, neural stem cells) and IPCs, and decreased the proliferation resulting from the prolong cell cycle length of IPCs in the SVZ. Our data show that maternal oral exposure to BPA related to the disruption of the cell cycle in IPCs and the effects of neurogenesis in the developing neocortex.