A Stereological Study On Human Placenta In Severe Preeclampsia

Backgroundpre-eclampsia is a disease which happens during pregnancy,and it's main clinical manifestation is multisystem functional disorder with hypertension,Urine protein level improve and edema.It is a major cause of maternal and fetal morbidity and mortality.According to the blood pressure and proteinuria levels,pre-eclampsia can be sort to light pre-eclampsia and severe pre-eclampsia.Especially,severe pre-eclampsia is dangerous to mater and fetus.An American scholar introduced the concept of Early-onset Severe Preeclampsia (EOSP)in the 1980s.In our country the scholar Yang-Zi defined the one onste before 32 weeks EOSP and the one onste after 32 weeks are called Late-onset severe Preeclampsia(LOSP).Recentlly,the medical workers of obstetrics paid more attention and shew their interesting to the EOSP.The EOSP incidence rate during pregnancy is 5%～7%,accounts for 20.4%of severe preeclampsism.It is an important cause of death of maternal and fetal.How to prevent and cure EOSP is a formidable problem to the medical wokers.There are many different views in the existing researches of pathogenesis of EOSP and LOSP,Kadyrov observed full-thickness of placenta,found that the apoptosis in placenta of patient with EOSP obviously increased.The invasion of trophocyte was restricted,placenta nidation was shallow and spiral artery was stenosal.So Crispi considered that EOSP was a placental desease,then the LOSP was a maternal one.Owing to the clinical symptoms is relieved after the placental expulsion,the relations between pathologic changes of the placenta and severe preeclampsia causes more and more attentions of researchers.Placenta is an organ which plays an important role in the point of circulation between mothers and fetus of metabolic change,of the hormonal and of immunological ones.With the development of science technical,the study of placenta is widely related with embryo,biochemistry,reproduction immunity and molecular biology,but the pathology of placenta is remain primary.Recentlly, immunohistochemistry,ultrasonics and some other methods were used in the study of placenta,a lot of change of structure and ultrastructure was observed and detected, thereby it offered some instruction to the clinical diagnosis and treatment.At the present stage,the study of placenta is mostly morphological,stereology is science which gets three-dimensional structure informations from two-dimentional structure.The use of stereology can quantitatively reveal the change characteristic of placenta.Objective:Through the observation of placenta in pregnant women with severe preeclampsia under light microscope and electron microscope the evaluation of stereology parameter to reveal quantitatively the characteristics and changing on the placenta. and further to explain the morphologic features and the association with fetal bad prognosis.Materials and Methods:1.The resource of MaterialsThe placenta tissues were obtained from women who deliveried in ZhuJiang hospital,Qing Xin hospital and Huang Qi hospital between 2007.9～2008.6,all of them knew the facts and agreed.2.Groups:severe pre-eclampsia groups:According to the diagnostic standard (OBSTETRICS AND GYNECOLOGY edited by Yuejie,the seventh edition).The study population consists of 20 in-patients,and the subjects were divided two groups:(1)LOSP group(≥32 weeks,n=10);(2)EOSP group(＜32weeks,n=10). There were no statistical differences between control and severe pre-eclampsia in maternal age and gestational age(P＞0.05).Control groups:the placenta tissues were get from premature delivery and term delivery women,and were divided two groups:(1)control groupA(≥32 weeks, n=10);(2)control group B(＜32weeks,n=10).There were no statistical differences between control and severe pre-eclampsia in maternal age and gestational age (P＞0.05),All cases had no other complications of pregnancy and complications of internal medicines.3.Preparation and measurement of specimens for light microscopeWhen the placenta delivered five pieces were selected from each placenta,each size was about 1cm×1cm×1cm,fixed by 4%formalin,imbedded by paraffin,then took 5 pieces of slices random,and stained by HE,each slice was observed by 40 times objective lens,then shot 5 pieces of nonoverlapping pictures random.The villus blood capillary volume density(Vv),surface density(Sv),numerical density (Nv)were measured,and the tests were done by the square grid test system made by Image-Pro analysis software.Each testing point is 30 pixels distant.Before testing the grid should be scaling,each testing point is 9.09μm distant.Use the formula to get the Vv,Sv,Nv.4.Preparation and measurement of specimens for electron microscope.As soon as the placenta delivered two pieces were selected from each placenta, each one was about 2mm×2mm×2mm,fixed by 2.5%glutaric dialdehyde,embedded by ozocerite and chip,then took 5 pieces of slices random,and stained by electron staining,Chips were observed by electron microscope type Hitachi H-7500,and shot 5 pieces of nonoverlapping pictures random.The Vv,Sv,Nv of syneytiotrophoblast mitochondrion,endoplasmic reticulum,Microvillares were measured,and the tests were done by the square grid test system made by Image-Pro analysis software.Each testing point is 20pixels distant.Before testing the grid should be scaling,each testing point is 0.1709μm distant.Use the formula to get the volume Vv,Sv,Nv.5.Methoes Observe respectively the change of placenta between EOSP group and control groupA,LOSP group and control groupB,and compared the difference of stereology parameter between them.6.Data processing and statistics analysisAdopting SPSS13.0 count software package to deal with the data:All datas were demonstrated in the way of mean±standard deviation.The means of two samples were executed by Independent-Sample t-test,and rates of sample executed in x~2(Fisher probabilities,n＜40),and the level of significance wasα=0.05.Results1.The results under light microscopeSyneytial cell knots was observed in control group A,fibrinoid necrosis villus was few,and there were many villus with(vasculo-syncytial membrane,VSM);In control group B syneytial cell knots and fibrinoid necrosis villus was few,the number of villus with VSM is large;In LOSP group there were many syneytial cell knots and fibrinoid necrosis villus,and less villus with VSM;In EOSP group syneytial cell knots and fibrinoid necrosis could also be observed,the number of villus with VSM is large.The stereoloyical study showed that the Vv and Nv of villi blood capillary in LOSP groups and EOSP groups was respectively smaller than in control group group A and control group B significanctly(P＜0.05),and there was no significant difference of the Sv in every two groups(P＞0.05).2.The results under electron microscopeOn the surface of syneytiotrophoblast in control groupA and control groupB, there was plenty of microvillus,well-arranged,mitochondrion and endoplasmic reticulum could be found anywhere in the cell,and there was fewer lipid granule;The paucity of syncytial microvillus was observed and the bottom of syncytial microvillus was swelen.The mitochondrion and endoplasmic reticulum were dilatational.The deposition of lipid granule was increased in LOSP group;and in EOSP group besides the changes in LOSP group the vacuoled enaturalization and less organell occurred in the placenta.The lipid granule was increased.The stereoloyical study showed that the Vv,Sv of mitochondrial in LOSP group were Significant augmentable than in control groupA(P＜0.05).Compared with control group B the Vv,Sv of endocytoplasmic reticulum was statistically increased(P＜0.05).There were no significant diference of Nv was found in mitochondrion and endoplasmic reticulum of every two groups (p＞0.05).The stereoloyical study showed that the Vv,Sv,Nv of microvilli in LOSP group and EOSP group was respectively smaller than in control group A and control group B significanctly(P＜0.05).3.The outcome of fetusIn LOSP group,the 10 patients was uterine-incision delivery,2 of them were fetal growth restriction(FGR),2 of them were neonatal asphyxia,and there was no neonatal death;In EOSP group,the 10 patients was uterine-incision delivery,3 of them were FGR,4 of them were neonatal asphyxia,the number of neonatal death is 2;In control group A 2 patients was uterine-incision delivery,8 Vaginal delivery, there were no FGR,neonatal asphyxia,neonatal death;In control group B,10 patients was Vaginal delivery,no FGR,neonatal asphyxia lcase,neonatal death 2cases.Conclusions1.severe Preeclampsia groups have more bad outcome.2.Under light microscope,the pathologic changes of the placental villous maybe resulted from the placental ischemia and hypoxia.3.Under electron microscope,the ultrastructure of syneytiotrophoblast in placenta was severely damaged in LOSP group and EOSP group.4.When severe preeclampsia happens,Probably organelle is impaired,and it results in abnormality of physiological function about syncytial cell and affect the synthesization and transportation of placental function.Maybe these participate in the injure of fetus.