The Role And Mechanism Of Aqp3 In Septic Pulmonary Vascular Leakage

Sepsis is the systemic inflammatory response caused by infection,which can cause severe organ failure and higher morbidity and mortality.Increased vascular permeability is an important pathophysiological process of sepsis,which is one of the important causes of organ dysfunction.A large number of studies on the mechanism and prevention for sepsis induced vascular permeability have been done,but the mechanism still need to be further clarified.Aquaporin(Aqp)is a membrane transporter that mediates water pass through cell membrane.There are 12 subtypes of Aqp in rats,and all subtypes have different expression and function in various organs.Studies found Aqp is not only a channel regulating water,glycerol and other small molecules' transport,but also could be a signaling molecule mediated cell migration,differentiation,secretion and other functions.Recent studies found that Aqp plays an important role in the pathophysiological processes of cerebral ischemia,hypoxia-reperfusion injury,tumor,nephropathy,retinal injury and Sjogren's syndrome.At the same time,Aqp also plays an important role in vascular permeability-related disease.Whether Aqp is involved in the regulation of pulmonary vascular permeability in sepsis and which Aqp plays a major role is unclear.Therefore,rat cecal ligation and puncture(CLP)sepsis model was used in the present study and following contents studied(1)the effect of Aqp3 on pulmonary vascular permeability in sepsis;(2)the mechanism of Aqp3 on pulmonary vascular permeability in sepsis;(3)The protective effect of SS-31 on pulmonary vascular permeability.The main experimental methods:The septic model was reconstructed by cecal ligation and puncture(CLP);Primary pulmonary vein endothelial cells from rat were extracted and cultured;The pulmonary veins and endothelial cells 's RNA and total protein were extracted;The expression of Aqp3 in the pulmonary vein was detected by PCR;The changes of Aqp3,Cav-1 and Occludin in the pulmonary veins and endothelial cells were detected by western blotting;Fluorescent albumin labeled isothiocyanate fluorescein was used to detect the pulmonary vascular and endothelial cell permeability;The changes of ROS in the pulmonary veins and endothelial cells were measured by the ROS kit;The expression of Aqp3 was disturbed by using small RNA.The main results:Part ?.Role of Aqp3 in pulmonary vascular permeability after sepsis in rats1.The expression of Aqps' RNA in the pulmonary vein of sepsis rats was enhanced,including Aqp1,3,4,7,11 and 12,among which Aqp3 was increased most.In vivo,pulmonary vascular permeability and Aqp3 expression were all increased as sepsis prolonger(6h and 12h)as compared with the sham operation group.The changes of Aqp3 expression were positively correlated with pulmonary vascular permeability;in vitro,the pulmonary vascular endothelial cell permeability as well as Aqp3 expression were also significantly increased at 6h and 12 h after LPS stimulation.2.In vitro interference of Aqp3 effectively antagonized the increase of endothelial cell permeability caused by LPS stimulationPart ?.The mechanisms of Aqp3 regulating pulmonary vascular permeability in sepsis1.After sepsis,the expression of Cav-1 was enhanced and the expression of Occludin was attenuated.In vitro,the expression of Cav-1 was enhanced and the expression of Occludin was decreased in pulmonary vein endothelial cells after LPS stimulation.The results were consistent with the change of whole animal level.2.Interference of Aqp3 in vitro antagonized the increase of Cav-1 and decrease of Occludin in pulmonary vein endothelial cell caused by LPS stimulation.Part ? SS-31 protected pulmonary vascular permeability in sepsis through the Aqp31.The expression of ROS in the pulmonary vein of rats was increased after sepsis.Pretreatment with SS-31 could antagonize the increase of ROS in sepsis.Meanwhile,pretreating septic rat with SS-31 could antagonize the increase of pulmonary vascular permeability and Aqp3 expression.2.In vitro,the expression of ROS in pulmonary vein endothelial cells was increased by LPS stimulation,and could be inhibited by SS-31 pretreatment.Meanwhile,pretreatment with SS-31 could antagonize the increased expression of endothelial cell permeability and Aqp3 expression in pulmonary vein endothelial cell stimulated by LPS,which was consistent with animal experiment.3.Pretreatment with SS-31 can improve the survival rate and survival time of sepsis rats.Conclusion:1.Aqp3 plays an important role in increased pulmonary vascular permeability after sepsis;2.Aqp3 regulating of pulmonary vascular permeability in sepsis may be involved both in transcellular pathway and paracellular pathway;3.SS-31 regulates the Aqp3 expression and protects pulmonary vascular permeability possibly by anti-oxidative stress.