Study On Activation Of NF-κB In Pulmonary Arterial Endothelial Cell Of Vascular Remolding Induced By High Blood Flow

BackgroundCongenital heart disease is a common congenital malformation,with 7%o-8%o incidence.Pulmonary hypertension develop in every development stage of congenital heart disease,therefore, many clinical doctors, at home and abroad,pay close attention to the treatment of left-to-right shunt cogenital heart disease.Pulmonary flow increases in left-to-right shunt cogenital heart disease,which makes shear stress to pulmonary artery increase,lead to pathological changes of structure and function pulmonary in arterial endothelium,thus,vascular endothelium is markedly damaged.Close behind,the barrier function of endothelium and endothelial-mucular conjunction are damaged,meanwhile the mechnism of endothelium modulating vascular smooth muscle cells,which induce vascular endothelial cells to proliferate uncontrolledly.So,pulmonary vascular remolding happens.On the one hand,it is a adaptive change to enviroment,the other hand, it is the physiopathologic found of pulmonary hypertension.Vascular endothelial cell that lies on the surface layer sensing blood flow is a physiological barrier,a sensor and a centor of production of conductive mediators.It can convert stress to biological effect.Accordingly,vascular endothelium plays an important part in angiotasis and pulmonary artery pressure.If increased pulmonary flow exceeds a limit,which damages regulation mechnism of endothelium to angiotasis,pulmonary hypertension happens. In 1986,Sen and Baltimore firstly detect a neucleoprotein factor which can specially bind to gene enhanserκB sequence(GGG ACT TTC) of immunoglobulinκL-chain,which is called NF-κB.After this,it is found in many kinds of cells,including vascular endothelial cells,smooth muscle cells and cardiac muscle cells. NF-κB can bind to specified nucleotide sequence of promotor domain,to start genetic transcription in immune response,inflammatory reaction and growth regulation of cells,which relate to diverse of onset and development of cardiovascular diseases. NF-κB is the most important nuclear factor in cells and plays a crucial part in signal transduction mediated by cell stimulus.Factors which can activate NF-κB are great deal,including various kinds of irritable stimulus,multiple cytokins(e.g.TNF-a,IL-1β),mitogen, oxygen free radical,protein kinase C,et al.When above-mentioned stimulus effect cells, protein kinases are activated, which make Sef32/36 of IκBa protein-regulation domain phosphorylates,and then 2 diaminocaproic acid residue of N-terminal bind to ubiquitin-ubiquitination. At last under the proteasome'function, IκBαschizolysis, nuclear localization signal on Rel protein snagged,lead to NF-κB-IκB-compound resolute,as result activated NF-κB rapidly enter into nucleus and specialy bind toκB site at target gene to start and regulate transcription of related target gene.Study confirm that vascular endothelial cell suffer outside stimulus,then firstly activate NF-κB,the latter bind to cell adhesion molecule gene and make it expression up-regulate.These adhesion molecule genes contain binding sites of NF-κB,which play an important part in coherence,invasion and immagration to blood vessel of white blood cell.So, activation of NF-κB is deemed to one of the start-up mechnism of damage to vascular endothelial cell.We study NF-κB activated condition of endothelial cell and cytobiologic function mediated by it to influence on pulmonary hypertension and regulation,which play an important part in understanding cause and target intervention treatment of pulmonary hypertension. ObjectiveThrough detecting activation of NF-κB in pulmonary endothelial cells of pulmonary vacular remolding induced by high blood flow and changes after given a block agent (PDTC) of NF-κB,the study conduce to search for physiopathologic causes of pulmonary hypertension induced by high pulmonary blood and provide theory basis and new path to PH by regulating NF-κB pathway to inhibite proliferation of pulmonary vascular smooth muscle cells.Research MethodsNumber 50 Wistar rats,aged 4w,randomly group 4 by computer,shunt group (Tn) 15,blocked by PDTC after operation group(Ti) 15,sham operation control group(Co) 10,negative control group 10 (Cn).30 rats(Tn+Ti) are seted up left common carotid artery-left external jugular vein shunt by telescoped joint,of the total 15 rats(Ti group) are given PDTC by intraperitoneal injection before operation lh,dosage 12Omg·kg-1·d-1after this,continue 2w;except not undertaking shunt operation,Co group rats own the identical operative procedure.After conscutively raising 12w, cardiac catheterization are used to survey pulmonary arterial systolic pressure,to calculate Qp/Qs;After then, to open the chest and remove the lung and the heart;Calculate the weight ratio of right ventricle and left ventricle plus septum to estimate the hypertrophy of the right ventricle.Lung tissue slices dyed by HE are observed in morphologic change of pulmonary vessels by light microscope,measure and calculate MT%(percentage of tunica media thickness making for caliber) of medium vessles.Dissociate pulmonary arterial endothelial cells,extract neucleoprotein,prepare DNA primer,determine the binding activity of endothelial cells in every group and special gene recognition sequence by ESMA(electrophoretic mobility shift assay)Research Results①Left common carotid artery-left external jugular vein shunt lead to increase of pulmonary blood flow,the general average of Qp/Qs is 2.32±0.44.Compared to Cn group,PASP of Tn group significantly increases(P<0.01),the increase of Ti group'PASP have no statistical significance(P>0.05). Cn group and Co group have no significant difference.②Compared to control group, Tn group,pulmonary arterial lumina narrow or occlude;endomembranes thicken,part of them ablate;vacular smooth muscle cell array disorder,hyperplasia and hypertrophy;Ti group,endomembrane swells,some of them ablate,tunica media is not obviously thickening;Cn group and Co group have no significant difference.Tn group,MT% and RV/(LV+SP) significantly higher than control group (P<0.01);Ti group compared to control group, MT% and RV/(LV+SP) have no significant difference.③Ti group activation of NF-κB is significantly higher than control group (P<0.01),Tn group significantly lower than control (P＜0.01).ConclusionRat pulmonary blood vessels construction and constructure remolding are related to augmented activaty of NF-κB.PDTC can interfere in pulmonary vascular remolding by blocking NF-κB signaling way induced by high blood flow.