Study On The Mechanism Of Wnt/β-catenin Pathway In Bronchopulmonary Dysplasia Induced By Chorioamnionitis

Objective:In this study,we investigated the key of the Wnt signaling pathway and the activation and regulation of Th17/Treg in the lung tissue of rats with BPD induced by chorioamnionitis(CAM),to elucidate the possible mechanism of the Wnt/β-catenin signaling pathway in BPD induced by CAM.Methods:1.Stablishment of a chorioamnionitis-induced bronchopulmonary dysplasia rat model:SPF grade SD Rats at 17 days of gestation were injected intraperitoneally with lipopolysaccharide(LPS-O55:B5)350μg/kg,for two days to induce intrauterine chorioamnionitis infection,and the newborn rats with bronchopulmonary dysplasia was obtained.2.Experimental grouping:the BPD model group:pregnant rat was induced by intraperitoneal injection of LPS 350μg/kg,which resulted in bronchopulmonary dysplasia induced by intrauterine Chorioamnionitis;Control group:newborn mice were obtained by intraperitoneal injection the same amount of 0.9%normal saline in the pregnant rat.3.Detection indicators:10 rats were randomly selected on the 1th,7th,and 14th days after birth(P1,P7,P14)in each of two groups to obtain lung tissue and peripheral blood samples.HE pathological examination was used to confirm the success of the model,Western blot to deleted the expression ofβ-catenin and ROR gamma t(RORγt)protein in lung tissue in two groups,Flow cytometry to detect Th17,Treg,and Foxp3~+in CD4~+T cells in peripheral blood of two groups,ELISA to detect the concentration of IL-17.Results:1.Hematoxylin-eosin staining:Verification of chorioamnionitis:vascular congestion and neutrophil infiltration can be seen in the placenta.Verification of animal model of bronchopulmonary dysplasia:HE staining of lung tissue showed that lung development was retarded and alveoli were simplified from P1,P7,and P14.2.Expression ofβ-catenin Protein:In the lung issue of the two groups,the expression ofβ-catenin protein increased gradually,BPD group was higher than the control group;the two groups were statistically different at three-time points(P<0.001).3.Expression of RORγt Protein:In the control group,the expression of RORγt protein increased gradually,and the highest expression of P7 decreased at P14 in the BPD group,BPD group was higher than the control group;the two groups were statistically different at P1 and P7(P<0.05),there was no statistically different at P14(P>0.05).4.Percentage of Th17:In the peripheral blood of the two groups,the percentage of Th17 increased gradually,and the highest expression of P7decreased at P14,BPD group was higher than the control group;the two groups were statistically different at three-time points(P<0.05).5.Percentage of Foxp3~+T cells:In the peripheral blood in control groups,the percentage of Foxp3~+T cell decreased gradually,and the highest expression of P7 and decreased at P14 in the BPD group,BPD group was higher than the control group;two groups were statistically significant three-time points(P<0.05).6.Percentage of CD25~+Treg:In the peripheral blood of the two groups,the percentage of Treg increased gradually,and the highest expression of P7 decreased at P14,BPD group was higher than the control group;the two groups were statistically significant at P1 and P7(P<0.05,there was no statistically different at P14(P>0.05).7.IL-17 levels:the level of IL-17 in two groups decreased gradually,and the highest expression of P7 decreased at P14,BPD group was higher than the control group;the two groups had statistical significance at P1 and P7(P<0.05),there was no statistical significance at P14(P>0.05).Conclusion:1.Lipopolysaccharide(LPS)350μg/kg was injected intraperitoneally for 2consecutive days can cause the newborn mouse bronchopulmonary dysplasia model induced by chorioamnionitis.2.In the chorioamnionitis-induced bronchopulmonary dysplasia rat model,β-catenin protein express abnormality,the Wnt/β-catenin signal pathway is anomalous activation,core moleculeβ-catenin has a prominently increased expression trend.3.In the chorioamnionitis-induced bronchopulmonary dysplasia rat model,β-catenin may mediate the formation of Th17/Treg in BPD by regulating Rorγt/Foxp3.