Expression Of High Mobility Group Box 1 And TLR4 In The Placenta Tissue Of Patients With Preeclampsia

Background and aimPreeclampsia is a commom disease in obstetrics and gynecology,it is a pregnan-cy specific systemic disease which may be associated with multiple organ dysfuncti-on or failure.Preeclampsia is one important reason for the increased maternal and pe-rinatal morbidity and mortality.Many scholars have done a lot of studies about pree-clamsia,however,the etiology and pathogenesis of preeclamsia still can not be clarified.Vascular endothelial cell injury and dysfunction is a central link in the pathogenesis of preeclampsia.The high mobility group box 1 (HMGB1) is a kind of nucleoprotein,because of its high mobility rate,we named it HMGB1.In 1999,Wang et al first found that as an important inflammatory cytokines,HMGB1 is released into the extracellular and mediate inflammatory response,HMGB1 plays an important role in the local and systemic inflammatory diseases.It is found that HMGB1 roled as a late inflammatory factor involves in the pathological process of endotoxemia,systemic lupus erythematosus, pulmonary fibrosis, rheumatoid arthritis, viral hepatitis, acute pancreatitis and other diseases.When combining with its recepters such as receptor for advanced glyeationend produets (RAGE),Toll like receptor 4(TLR4),TLR2,HMGB1 can promote inflammatory response. TLR4 is a transmembrane receptor which is the most widely distributed TLR of TLRs family members.In the present study,it is confirmed that TLR4 plays a key role in the resistance to the invasion of external pathogenic microorganisms,it can identify bacteria,viruses and other pathogens.When it is stimulated by biological ligands such as heat shock protein(HSP)and HMGB1,TLR4 can transmit its signal to the intracellular,leading to the activation of inflammatory factors NF-κB,which can cascade active its downstream inflammatory factors,resulting in the waterfall like release of a variety of inflammatory factors.In this study, we use the real time polymerase chain reaction(PT-PCR)for the determination of HMGB1 and TLR4 mRNA expression in placental tissue of normal pregnant women and patients with preeclampsia,use immunohistochemical(IHC) to determin their two proteins’ location and expression,then analysis the correlation between HMGB1 and TLR4.Materials and Methods1 Clinical medical date60 patients with preeclampsia (30 cases of mild preeclampsia and 30 cases of severe preeclampsia) and 30 cases of normal term pregnancy were selected from the First Affiliated Hospital of Zhengzhou University Hospital to detect HMGB1 and TL-R4 mRNA and their protein in the placenta tissue by semi-quantitative PCR and immunohistochemistry.They all deliver by caesarean section.The average age and deliver weeks of mild preeclampsia are (28.97±4.99)years and (36.93±2.68) weeks,while the severe preeclampsia patients’ are (30.57±5.41)years and (35.1±2.79) weeks,the normal pregnant women’ are(29.03±4.77)years and (38.83±2.76)weeks (most normal women were cephalopelvic disproportion、breech and placenta previa).Diagnostic standard for preeclampsia is referenced to the national institutions of higher learning for Obstetrics and Gynecology,7th edited by Le Jie.All of the subjects were excluded from the history of hypertension,heart disease,liver disease,kidney disease, diabetes, thyroid function, hyperthyroidism, etc, without smoking,drinking, blood transfusion, history of immunotherapy. 2 Experimental methodsHMGB1 and TLR4 mRNA expression were detected by RT-PCR;location and expression of their proteins were detected by HIC.3 statistical analysisSPSS 17.0 software was used for statistical analysis,the results were expressed with x±s,count data was analyzed by theχ2 test,the measurement data was analyzed by one way ANOVA.The correlation of HMGB1 and TLR4 was analysed by Pearson productmoment correlation analysis.Statistical signifieance level was 0.05.Experimental results1. The expression levels of HMGB1 mRNA in the placenta tissue of mild and severe preeclampsia were higher than normal control group,and the difference has statistical significance(Pm=0.000,Ps=0.000),but there was no significant difference between mild and severe preeclampsia (P=0.256);The expression levels of TLR4 mRNA in in the placenta tissue of mild and severe preeclampsia were higher than normal control group,the difference has statistical significance (Pm=0.000,Ps=0.000), but there was no significant difference between mild and severe preeclampsia (P= 0.130).2. The HMGB1 protein was mainly expressed in the cytoplasm of trophoblastic, a small amount expressed in the cytoplasm of mesenchymal cells and vascular endothelial cell.The expression levels of HMGB1 protein in mild and severe preeclampsia were higher than normal control group,and the difference has statistical significance(Pm=0.032,Ps=0.018),but there was no significant difference between mild and severe preeclampsia (P=0.605);The TLR4 protein was mainly expressed in the membrane and cytoplasm of trophoblastic,a small amount expressed in the mesenchymal cells.The expression levels of TLR4 protein in mild and severe preeclampsia group were higher than normal control group,the difference has statistical significance(Pm=0.038,Ps=0.002),but there was no significant difference between mild and severe preeclampsia (P= 0.273).3. The expression levels of HMGB1 and TLR4 in the placenta in preeclampsia was positively correlated (mRNA level r1=0.862, P1=0.000; protein levels r2=0.825, P2=0.000).ConclusionThe expression of HMGB1 and TLR4 mRNA and their protein were elevated in the placenta in preeclampsia,suggesting that they may play an important role in the pathogenesis of preeclampsia.There were positive correlation in mRNA and protein levels between HMGB1 and TLR4,which suggest a synergistical effect between them in promoting the development of preeclampsia.