| Preeclampsia(PE)is a pregnancy-specific disease which seriously harms the health of the mother and the child and affects almost all organs of the body.Therefore,it is extremely important to find the corresponding therapeutic drugs.The etiology of PE is still unknown,but it is generally recognized that over-activation of inflammatory immune system is an important pathogenesis.And over-activation of TLR4 signaling pathway is an important bridge linking the placental shallow implantation and dysfunction of whole-body endothelial cells.The statins have not only the most important lipid-lowering effect but also the effects of anti-inflammation,anti-hypertension,improving vascular endothelial function,and so on.Among them,pravastatin,which has strong polarity,the characteristic that can hardly penetrate placenta and relatively weak inhibition of HMG-Co A reeducates,has attracted attention in the prevention and treatment of PE.However,we wonder that whether pravastatin can inhibit the over-activation of TLR4 signaling pathway so as to improve the function of trophoblast cells,as well as whether its effect of inhibiting cholesterol synthesis has serious impact on offspring development.In this study,the PE model induced by LPS-induced activation of rat TLR4 pathway was used to observe the therapeutic effect of pravastatin on PE model.The study included the following three parts:In the first part,18 SD pregnant rats were randomly divided into 3 groups.In the control group,2 ml of physiological saline was injected into the rat tail vein on the gestational day(GD)5;rats in the LPS model group and the statin group were injected with 0.5 ?g/kg of lipopolysaccharide(LPS)in the rat tail vein on GD5.And rats in thestatin group were given administration of pravastatin 1 mg/d orally from GD5 to GD19.The changes in rats' phenotype,rats' placental pathology,and the changes of key molecules in TLR4 signaling pathway were observed.In the second part,we investigated the relationship between over-activation of inflammatory immunity and changes in placental autophagy in the placenta of rat model.In vitro experiments of human villous trophoblast cells were used to study the changes in autophagy,the effect of pravastatin on this change,as well as the relationship with the invasion function of trophoblast cells after the stimulation of LPS on human villous trophoblast cells through the Transwell chambers,electron microscopy,immunofluorescence,and reporter gene technology.In the third part,the changes of serum cholesterol in maternal rats after administration of pravastatin 1 mg/d were studied.The weight changes of fetal rats' bodies and brains,livers as well as kidneys in the LPS-induced PE model group,the pravastatin intervention group and the saline control group were compared.The effects of pravastatin treatment on brain,liver and kidney structure of fetal rats during pregnancy were observed.The results of the first part showed that the blood pressure of the control group,LPS group,and statin group before intervention on GD3 were 100.83±0.64,100.00±0.78 and100±1.20 mm Hg,with p > 0.05;urine proteins were 1730.12±142.56,1746.85±205.83 and 1626.26±233.08 ?g,respectively,with p > 0.05.When given LPS stimulation on GD5,blood pressure of the statin group decreased on GD9(103.50±1.39 mm Hg),which was not significantly different from that of the control group(101.17±1.23 mm Hg)and was significantly lower than that of the LPS group(116.5±0.70 mm Hg)(p < 0.05).On the same day,urine proteins of the pravastatin group decreased(1991.03±248.77 ?g),which were not significantly different from those of the control group(1820.12±221.20?g),and these two groups were significantly lower than those of the LPS group(3726.23±642.12 ?g).After pravastatin treatment,the expressions of TLR4 and NF-?B-p65 in the placenta were significantly lower than those of LPS model rats(p <0.05),which were not statistically different from those of the control group.Pravastatin treatment improved insufficient spiral arterial remodeling in LPS-induced PE model rats.And the fetal growth restriction in the pravastatin group was 8.99%(8/89),which was significantly lower than 34.10%(30/88)in the LPS group(p < 0.05),and was not statistically different from 8.89%(8/90)in the control group(p > 0.05).In the second part,the expressions of autophagy-related proteins LC3 and Beclin-1in placenta of PE rat model increased,and the expression level of p62 decreased.The expressions of three proteins above in the PE model rats were similar to the clinical results.However,after pravastatin treatment,the expressions of LC3 and Beclin-1 were lower than those of the LPS group,and the expression level of p62 increased.The results of electron microscopy showed that the number of placental autophagic vacuoles in the LPS group was more than that in the control and statin groups.After LPS stimulation on HTR-8/SVneo,the observation results of LC3 detected by immunofluorescence showed increased autophagic vacuoles,while they decreased after pravastatin treatment.In addition,the invasive function of HTR-8/SVneo in the pravastatin group was significantly better than that in the LPS group.LPS activated NF-?B-p65,thereby affecting its binding site with the Beclin-1 promoter region,and promoting the expression of Beclin-1 from the transcriptional level,while pravastatin treatment reduced overexpressed NF-?B-p65 so as to inhibit Beclin-1 expression.The results of the third part showed that the serum total cholesterol levels of the mother rats in the control group,LPS group and statin group on the 19 th day of pregnancy were 1.07±0.13,1.07±0.19,1.08±0.19 mmol/L,with p > 0.05.The brain weights of fetal rats in the control group,LPS group and statin group were 118.53±1.28,110.75±1.12 and 117.87±1.42 mg;the fetal liver weights were 153.22±3.58,127.37±2.67 and 149.12±3.23 mg,respectively;the fetal kidney weights were 5.50±0.15,4.09±0.11 and 5.45±0.12 mg,respectively.The weight of each organ in the LPS group was significantly lower than that of the control and pravastatin group(p < 0.05).And there was no significant statistic difference between the control group and the pravastatingroup.HE staining showed no abnormalities in the structure of the organs of fetal rats in the three groups.In summary,pravastatin can improve the remodeling of spiral arteries in LPS-induced PE model rats by inhibiting over-activation of TLR4 signaling pathway,thereby improving PE-like phenotypes of hypertension,proteinuria and FGR of the model group.The PE model rats were treated with pravastatin equivalent to twice the dose of human drug,and no abnormalities in fetal rat structure and weight were found.It was suggested that pravastatin may be further studied as a potential drug for the treatment of PE. |
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