| Steroid hormones especially estrogen and progesterone play important role during pregnancy.The normal levels of estrogen and progesterone are not only crucial for successful establishment of pregnancy,but also vital for the maintenance of pregnancy.The placenta is a transitional organ formed by the embryo's embryonic membrane and the mother's endometrium in early pregnancy.Placenta mediates nutrient and waste exchange to enable in utero existence.In addition,placental vascularization is important for the maternal-fetal exchange function.Therefore,the maintaining of enough numbers of placental blood vessels throughout the whole pregnancy period is of great significance.Objective:To study the effect of short-term inhibition of estrogen synthesis on the placental development of rats after implantation.Methods:Rats in the experimental group were given letrozole at a dosage of 0.16 mg/kg/d for three consecutive days on day 6.5,7.5 and 8.5 of pregnancy,and rats in the control group were intragastric administration of 0.5%sodium carboxymethylcellulose solution at the same time point,tail vein blood were collected to measure the peripheral blood estrogen levels,placenta were separated on day 16.5,19.5 and 22.5 of pregnancy and weighed,H&E staining were performed and CD34 expression were detected to evaluate the development of placental vascular;E2(10-10,10-9,10-8,10-7,10-6 mol/L)at different concentrations were co-cultured with HUVECs,blank control group was set up,the CCK-8 was used to detect the viability of HUVECs,the scratch test was used to detect the migration function of HUVEC,the transweel test was used to observe the invasion function of HUVEC,the tube formation test was used to evaluate the tube formation function of HUVEC,Real-time PCR detection of Vegf mRNA expression;rat embryonic tissue microarrays were used to analyze the differentially expressed genes between the experimental and control group,the effects of ANGPTL8 and CXCL12 on the migration,invasion and tube forming ability of HUVECs were detected by cell migration,invasion and tube forming experiments,the influence of angptl8 on the expression of CXCL12 in htr8 cells was analyzed by Western blot.Results:Compared with the control group,the weight of placenta in the experimental group increased significantly;the peripheral blood estrogen levels showed a downward trend in the experimental group and the development of placental vascular was significantly insufficient in contrast to the control group;10-8 mol/L of E2 group significantly promoted HUVECs proliferation,migration,invasion,tube formation and Vegf mRNA expression,and the 10--6mol/L E2 group significantly inhibited HUVEC proliferation,migration,invasion,tube formation and Vegf mRNA expression;compared with the control group,the expression of angptl8 was up-regulated and the expression of cxcl12 was down-regulated in the experimental group,angptl8 inhibited the migration,invasion and tube forming ability of HUVECs while CXCL12 enhanced the migration,invasion and tube forming ability of HUVECs,moreover,overexpression of angptl8 decreased the expression of CXCL12 in htr8.Conclusion:The placental hypertrophy rat model was successfully established,and the development of placental blood vessels in the experimental group exhibited pathological states;the effect of E2 on angiogenesis of HUVECs showed a dose-effect relationship,as the concentration of E2 increases,its roles in promoting the proliferation,migration,invasion,tube formation and Vegf mRNA expression of HUVECs increases,while at high concentrations it had an inhibitory effect;Rats temporarily suppress estrogen after implantation,the placental CXCL12 protein level is reduced,and the migration,invasion and tube formation of vascular endothelial cells are inhibited,ANGPTL8 inhibits the expression of CXCL12 in HTR8 cells,and it can also inhibit the migration,invasion and tube formation of vascular endothelium. |
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