Background: Maternal exposure to ambient fine particulate matters (PM2.5) is associated with low birth weight (LBW) in offspring, but the underlying biological mechanisms are not yet fully understood. As the bridge that connects mother and fetus, the placenta plays a crucial role in fetal development by providing the fetus with nutrients and oxygen. However, whether PM2.5 exposure would impact the placental development and the related mechanisms are unclear.
Results: In the present study, female C57Bl/6j mice were exposed to filtered air (FA) or concentrated ambient PM2.5 (CAP) during pregestational and gestational periods, and the fetal development and placental structure were investigated. Our results showed that maternal exposure to CAP induced fetal growth restriction (FGR) and LBW. The placenta from CAP-exposed mice exhibited abnormal development including significant decrease of surface area, smaller junctional zone and impaired spiral artery remodeling. Meanwhile, CAP exposure altered trophoblast lineage differentiation and disrupted the balance between angiogenic and angiostatic factors in placenta. In addition, the inflammatory cytokines levels in lung, placenta and serum were significantly increased after ambient PM2.5 exposure.
Conclusion: Our findings indicate that maternal exposure to PM2.5 disrupts normal structure and spiral artery remodeling of placenta and further induces FGR and LBW. This effect may be caused by the placental inflammation response subsequent to the pulmonary and systemic inflammation induced by ambient PM2.5 exposure.
Keywords: Fetal growth restriction; Inflammation; Maternal exposure; PM(2.5); Spiral artery remodeling.
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