Exposure To Benzo(a)pyrene Impairs Decidualization And Decidual Angiogenesis In Mice During Early Pregnancy

Objective:Benzo[a]pyrene(benzo(a) pyrene, BaP) is a ubiquitous environmental pollutant and a well-known endocrine disruptor. A large number of studies have indicated that the reproductive and endocrine systems are susceptible to occupational and environmental pollutants, one of which is benzo[a]pyrene. The studies of the reproductive toxicity of BaP are primarily focused on its effects on sex hormones, embryogenesis and fetal survival. However, those reports rarely paid attention to early pregnancy. In this study, we have specifically investigated the effects of BaP on the maternal uterine decidualization and decidual angiogenesis in mice during early pregnancy.Methods:1. Animals and treatment: Pregnant mice were exposed to BaP at 0.2, 2 and 20 mg/kg body weight from day 1. The control group was administered corn oil only. The mice were killed on days 6-8 respectively by cervical dislocation, and the uteri tissue were immediately excised.2. Enzyme-linked immunosorbent assay(ELISA) was applied to test the levels of estradiol and progesterone in serum.3. Real-time PCR, Western-blot and IHC were used to detect the mRNA and protein expression of estrogen receptor, progesterone receptor and decidualization related genes in the decidual tissue.Results:1. The mice exposed to BaP exhibited small and unevenly sized implantation sites.2. Decidualization defects were observed in the mice exposed to BaP.3. The estradiol and progesterone levels in BaP-treated groups were lower than those in the control group.eased in the BaP-treated groups.5. The key molecules related to decidualization were decreased in the treated group.6. Decidual angiogenesis were affected by BaP treatment.7. The expression of VEGFA(vascular endothelial growth factor A) was reduced in the BaP-treated group.Conclusion:Pregnant mice exposed to BaP decreased the level of estrogen and progesterone, inhibited the expression of their receptors. Key molecules related to decidualization were affected by BaP. Reduced decidual angiogenesis were observed in BaP treated group. These results suggest that BaP can impair the decidualization and decidual angiogenesis during early pregnancy, which might have adverse effect on the development of embryo.