Correlation Between Premature Rupture Of Membranes And Fetal-neonatal Lung Injury: Basic And Clinical Research

Premature rupture of membranes (PROM) is a common complication during pregnancywith an incidence of more than20%. PROM is a serious threat to maternal and childhealth and become a serious social problem. It is not only the most common cause ofpremature birth,and significantly increase the incidence of perinatal manydiseases.Especially the impact of the development of the fetus-neonatal lung.Previousstudies suggest that PROM can cause serious adverse effects on the fetus-newborn lungdevelopment and is closely related to variety of neonatal lung disease, but the directevidence of fetal-neonatal lung damage has not been reported, the specific mechanism isnot clear.The purpose of this study was as following:(1) pathological evidence of fetallung damage caused by premature rupture of membranes;(2) the main reason of thefetal lung damage caused by the premature rupture of membranes;(3) study thecorrelation between premature rupture of membranes and severe neonatal lung disease;(4) Pathogenic characteristics of neonatal infections caused by PROM, to provide areference for the prevention and treatment. Collected fetal lung tissue samples of four cases in Capital Medical University, BeijingMaternity Hospital due to stillbirth, stillbirth, induced abortion or miscarriage in May2010-Sep2010.PROM group and non-PROM group,2cases from PROM group gestational age21weeks and24~+weeks， gestational age of the non-PROM group for21weeks and24+weeks. By HE staining of lung tissue sacrificing, optical microscopeand produced slice of the electron microscope electron microscope to understand thepathological changes of the fetal lung tissue in each group. Massive neutrophilinfiltration seen in the fetal lung tissue of rupture of membrane group, a viscous liquidand inflammatory cell exudation and a large number of red blood cells to leak into,confirmed the existence of infection and inflammation; the control group under theoptical microscope these pathological changes in light. Electron microscope can be seenin PROM group within the fetal lung tissue inflammatory cell infiltration, showing moreundifferentiated cuboidal cells, the nucleus, cytoplasm and organelles; alveolar type Ⅱcells (AEC-II) nucleus of solid shrinkage, irregular shape, showing darkly stainedheterochromatin, some of the cell membrane rupture, dissolution, visible expansion ofthe endoplasmic reticulum, mitochondria, occasionally discharged to the alveolar spacewas the secretory state of lamellar bodies and lamellar bodies debris. Control group canbe seen that a small amount of the AEC-II cell surface microvilli, organelles, glycogenmore start lamellar bodies. These results confirmed that rupture of membrane canindeed result in fetal lung tissue damage from the pathological point. Explore the change in the expression of pentraxin3(PTX-3)-mRNA and its clinicalsignificance in fetal lung tissues with intrauterine infection related to premature ruptureof membranes (PROM）. From Oct.2010to Oct.2011, a total of12cases of fetal death,stillbirth, abortion or miscarriage of fetal lung specimens were assigned to this studywhich were collected from Beijing Obstetrics and Gynecology Hospital. Fetal lungsamples were devided into two groups according to with (study group,6cases) or without (control group,6cases) intrauterine infection related to PROM.(1) Fetal lungtissue specimens were fixed with4g/L of paraformaldehyde and paraffin embeddedwithin2h,4m serial section, and then HE staining. Light microscope was used toidentify whether infection/inflammatory response existed in fetal lung tissues or not.(2)Total RNA samples from fresh lung tissure were reverse transcribed into Cdna. Glyceraldehyde-3-phosphate (GAPDH) was used as internal reference gene. SYBR GreenⅠ real-time fluorescence quantitative PCR (RT-PCR) and relative quantitative analysismethod were performed to detect the expression of mRNA in lung tissue in two groups.Relative expressions of mRNA in two groups were compared by△Ct method ofrelative quantification.(3)Dawaxing,antigen complex，DAB color on paraffin sections,observed under the microscope,each slice were randomly selected five fileds at200times the light microscope to observe the distribution and expression of the protein,andimage analysis.Results (1) There was a large number of neutrophil infiltration, redblood cells leakage, viscous liquid and inflammatory cell exudation in fetal lung tissuesof study group, while compared with control group.(2)Study group displayed higherexpression of PTX-3-mRNA than in control group.(5.81±0.63) vs.(4.20±0.70),respectively (t=4.84，p=0.002).(3)PTX-3protein expression in the PROM group（0.1050±0.0121）(Figure10), and were of this character in different parts of the lungtissue. In non-PROM group（0.0932±0.0261），, also exists in different parts of the lungtissue, the difference was statistically significant （t=4.62， p=0.001）。Conclusions:The expression of PTX-3-mRNA was significantly increased in fetal lung tissues withintrauterine infection related with PROM, which can be regared as a sensitive index forthe early diagnosis of fetal intrauterine infection when PROM exists. The results of previously study shows that closely related to PROM and fetal lunginjury, but its relationship with the newborns with severe lung disease has yet to bestudied. Respiratory distress syndrome (RDS) is a neonatal clinical common seriouspulmonary diseases, is one of the common causes of neonatal deaths. This section byexploring the correlation of rupture of membrane and full-term newborns with RDS to apreliminary understanding of the relationship between PROM and neonatal intensivepulmonary disease.This study was assigned to investigate the correlation betweenPROM and RDS in full-term neonates by a large sample case-control study. The studywas designed as a case-control study.From Jan.2008to Dec.2010, a total of205full-term newborns with RDS were included in the study group who were administrated inthe Department of Neonatology＆NICU, Bayi Children’s Hospital Affiliated WithGeneral Hospital of Beijing Military Command. At the same periods,410full-termneonates without RDS were assigned as control group. Results:1.The incidence rate ofPROM was30.2%（62/205） in RDS patients as higher as compared to those withoutRDS patients（χ2=7.216，P<0.05）.2.Univariate analysis showed that PROM, selectivecesarean section, male, SGA, less amniotic fluid,gestastional high blood suger anddiabete, III contamination of amniotic fluid, fetal distress, birth asphyxia and otherfactors are the main risk factors of full-term neonatal RDS (p <0.05).3.The Logisticregression analysis showed that PROM,selective cesarean section, male, low birthweight,Gestational glucose abnormoalities,and birth asphyxia was closely correlatedwith RDS in full-term newborns. Conclusions: PROM is closely correlated with RDS infull-term neonats, this finding is significance for the clinical management of RDS interm newborns. Our previous results proved that PROM is closely related to fetal lung injury and neonates with severe pulmonary disease, infection and inflammatory response play animportant role in neonatal lung injury, Therefore, understanding which pathogen canleading neonatal infection has important clinical significance when promhappened.From May2007to November2010,16356neonates who were admitted toBayi Children’s Hospital were assigned to this study. The related clinical andlaboratorial information were recorded, which including with or without PROM andtime of duration, results of blood culture, C-reactive protein (CRP), chest X-ray findingsand other clinical data. Results①A total of3432patients accompanyed with PROMamong16356infants （21.0%）, There were1060full-term neonates (30.9%)and2372premature infants(69.1%) among3432PROM case. The incidence of infectious diseasewas35.8%(1227/3432) in infants with PROM:10.5%（111/1060） in term infants and6.3%(149/2372) in premature infants (χ2=18.370， P=0.000).②The commonpathogenic organisms were respectively gram positive (G+) cocci (58.5%) and gramnegative (G-) bacilli (33.8%)(χ2=31.695, P=0.000). The most common organismsincluded Staphylococcus epidermidis, Staphylococcus homis, Klebsiella pneumoniae,Escherichia coli and hemolytic staphylococci, account for75.8%of the total bloodculture positive patients. Fungal infection accounted for7.7%of the total infectiousdiseases and all of babies were premature infants.③The blood culture-positive rate ingroup of with PROM time duration <24h,≥24h and≥72h were7.7%(119/1544)、7.2%(99/1382), and9.6%（42/439）(χ2=2.701，P=0.259), respectively. Conclusions The mostcommon pathogens in infants with PROM is Staphylococcus epidermidis,Staphylococcus homis, Klebsiella pneumoniae, Escherichia coli and hemolyticstaphylococci, they account for more than75.0%of the total blood culture positivepatients.Besides,Fungiare detected mainly premature infantsblood culture-positive ratemay not increased with the extension of time of PROM.