Administration With Antioxidant MitoQ In Early Gestation Affects Placental Angiogenesis In Mice

Background:Placenta is an important barrier for material exchange at the maternal-fetal interface.The normal development of its internal dense vascular network is a prerequisite for the normal substance exchange,which is crucial for proper growth of fetus.It is generally believed that excessive reactive oxygen species（ROS）can cause oxidative stress（OS）,resulting in placenta-derived diseases,such as early-onset preeclampsia（PE）.Antioxidant administration could alleviate clinical manifestations in rodent PE model and pregnant women diagnosed with PE,but could not prevent PE before clinical symptoms.Moreover,appropriate ROS plays an important role in placental angiogenesis and trophoblast development in early pregnancy.Objective:To research the effect of ROS on angiogenesis during placentation,high-efficient antioxidant MitoQ was used in early pregnancy to reduce ROS content in placenta.Methods:Firstly,human and murine placental OS in different pregnancy stages were determined by MDA testing,the enzymatic activity of superoxide dismutase（SOD）and glutathione peroxidase（GPx）,Western blot and 4-hydroxynonenal（4HNE）staining.Then,normal pregnant mice were administered with MitoQ on GD8.5 to GD11.5 by gastric irrigation to observe the placental morphology from GD11.5 and GD18.5 by H&E staining.Besides,IHC staining of CD31 and serum s Flt-1 were tested on GD18.5.At the same time,Western blot was used to observe the protein expression of angiogenesis related pathway in placentas on GD11.5 and GD18.5 respectively.Finally,low-dose H₂O₂was applied onto HUVEC to determine the impacts on cell viability and ROS tested by CCK8 and ROS kit.On the basis of H₂O₂,MitoQ,AKT inhibitor and ERK1/2 inhibitor were applied onto HUVEC to evaluate cell viability and angiogenesis by CCK8,tube formation assay and Western blot.Results:The expression of MDA in human placenta and 4HNE in mice placenta were higher in early gestation and decreased with the prolongation of pregnancy,while the enzymatic activity of SOD and GPx did not change significantly between villi and term placenta.The amount of vasculature and blood sinus in placental labyrinth in MitoQ group reduced significantly on GD11.5 and GD18.5 compared with that in control group,and serum s Flt-1 increased remarkably in MitoQ group.Meanwhile,the expression of angiogenesis-related pathway in MitoQ group decreased both on GD11.5 and GD18.5.In vitro experiments showed that low-dose H₂O₂could promote cell proliferation,ROS increase and angiogenesis of HUVEC,while MitoQ,AKT inhibitor and ERK1/2 inhibitor could eliminate this effect.Conclusion:Appropriate ROS is essential for angiogenesis of placental endothelial cells;diminishing ROS by high-efficient antioxidant during early pregnancy is detrimental for placental angiogenesis and may increase the risk of PE.Therefore,the preventive use of antioxidants for normal pregnant women without symptoms in early gestation should be considered carefully.