| Objetctive Preeclampsia?PE?is a common pathological syndrome during pregnancy,and its pathogenesis is still unclear.Systemic small vasospasm is the main pathophysiological change.Previous studies in this study found that placenta in pregnant women with preeclampsia can produce and release a large number of placental-derived microvesicles?pcMVs?into the maternal blood circulation,suggesting the vasospasm is related to maternal and child complications in PE possibally.In this study,pcMVs were prepared from the placenta of the C57BL/6J mouse by the mechanical method and were injected via the tail vein.The effect of pcMVs on brain blood perfusion was observed by laser spackle test.The effect of pcMVs on vasospasm was observed by the arterial ring experiment.The effect of pcMVs on embryonic development in pregnant mice was observed.This study aimed to preliminarily explorate the mechanism of vasospasm in preeclampsia and provid new ideas and basis for the study of the pathogenesis of preeclampsia.Methods?1?C57 mice were paired with males and females at a ratio of 3:1,reared under standard conditions,and identified for the days of pregnancy.?2?pcMVs were obtained from the placenta of the C57 mouse by mechanical method and identified by electron microscopy,particle size measurement and flow cytometry counting;?3?In vitro,vascular ring tension test was used to detect the vasospasm of pcMVs on isolated arteries of non-pregnant mice;?4?In vivo,the effect of cerebral blood flow perfusion in mice was observed by laser speckle test;?5?At the 7th day of pregnancy,mice were injected with pcMVs for 1 week,and the placenta and embryos were collected at the 15th day of pregnancy.The size and weight of the placenta and embryo were measured,and the pathological changes were measured by HE staining.Results?1?The complete structure of pcMVs prepared in vitro was observed by transmission electron microscopy.The particle size detection also showed that the diameter of pcMVs was between 100-700 nm.The expression of AV-specific antibody on the surface of pcMVs by flow cytometry was 10.1%and can calculate the number of pcMVs;?2?In the isolated arterial ring test of the non-pregnant mouse,compared with the control,pcMVs can cause the contraction response of the vascular segment?2.283±0.248mN VS 0.200±0.063mN,P<0.001?;?3?After 17.2s±1.3s of injection of pcMVs in the tail vein,C57 mice showed a decrease in cerebral blood perfusion.The blood perfusion volume before injection was 352.342±33.564 PU,and the blood perfusion volume after injection was 210.532±41.971 PU.The blood perfusion was restored to 272.043±22.764PU.Compared with the normal group,the blood perfusion of the mice decreased significantly after injection of pcMVs?40.70%±8.57%vs 1.18%±1.98%,P<0.001?.And then blood flow recovered,but could not return to the normal level?77.73%±8.89%vs 100%±1.39%,P<0.001?;?4?Compared with the control,the number of embryos decreased after injection of pcMVs in pregnant mice?5.3N±1.2N VS 8.0N±0.9N,P=0.001?,the placental weight of pregnant mice was significantly reduced?0.082±0.010g VS 0.058±0.013g,P=0.004?,the weight of fetal mice was also significantly reduced?0.267±0.034g VS0.082±0.011g,P<0.001?,the placental diameter significantly shortened?0.827±0.046 cm VS 0.633±0.064 cm,P<0.001?.And the placenta maternal surface was obviously bleeding,the placental lost area have significantly reduced blood,leukocyte infiltration.Conclusion?1?In vivo and in vitro,pcMVs can cause vasospasm and can cause a decrease in blood perfusion in non-pregnant mice,suggesting that vasospasm caused by pcMVs may be associated with pre-eclampsia;?2?In vitro,pcMVs can lead to the destruction of the maternal surface structure of the placenta,inhibit the growth and development of the embryo.The study suggested that pcMVs may cause adverse embryonic development in preeclampsia by causing uterine-placental vasospasm. |
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