Effect And Significance Of RA On VEGF And ET Expression In The Lungs Of The Rat Models With Nitrofen-induced CDH

Objective To research the expression and significance of VEGF and ET in fetal rat lung with congenital diaphragmatic hernia(CDH)and evaluate the effect of intervention by Retionic Acid in fetal lung development of rat with CDH.Meterials and Methods 20 adult feminine Sprague-Dawley rats were divided into 4 groups(5 rats in each groups):1.Normal Control(NC);2.Retinoic Acid Control(RC);3.Congenital Diaphragmatic Hernia Normal Saline(CDH NS);4.Congenital Diaphragmatic Hernia Retinoic Acid(CDH RA).Each pregnant rats in group 1 and 2 was intragastric administration with olive oil 1ml on day 9.5 of gestation.Other groups' rats were administered 100 mg Nitrofen dissolved in olive oil 1 ml.From day 18.5 of pregnancy,NS 1ml/d was administered by intraperitoneal injection to each rat in group 1 and 2,and RA(dissolved in olive oil 1 ml)was administered by intraperitoneal injection to each rat in group 3 and 4 for three days.Then the fetuses were delivered by casarean section and executed by decollation on day 21.5 of gestation.The body weight and lung tissue weight of each fetus were recorded and confirm congenital diaphragmatic hernia(CDH).Lung histologic evaluate PAA(proprotianal alveolar area),MTBD(mean terminal bronchi density),MWT(proportional medial wall thickness)and RAC(axial acinar count),VEGF and ET immunohistochemistry staining evaluations were performed with image analysis.The expression of VEGF and ET in the fetal lung tissue were analyzed with orientation and quantitation.The experimental data were performed with statictical analysis.ResultsThe ratio of the fetuses with CDH of the fetuses in the group 3 and 4 was 48.8% and 36.7%,and the incidence rate of CDH in CDH RA group is lower than the CDH NS group respectively(P<0.05),there was no any CDH fetus in group 1 and 2.Lw/Bw of CDH groups are all lower than Control groups.The difference between the two groups had statistic significance(P<0.05).And in Control groups,the difference of Lw/Bw between group 1 and 2 had no statistic significance(P>0.05).In CDH groups,the difference of Lw/Bw between group 3 and 4 had no statistic significance(P>0.05).Light microscope observation manifested the pulmonary arterioles and bronchioles wall of Normal Control group were thin while the pulmonary arterioles and bronchioles wall of CDH NS group were thick.The pulmonary arterioles and bronchioles wall of CDH RA group were between the preceding two groups.But the Normal Control group and Retinoic Acid Control group had the same result.Image analysis and statictical analysis showed that the difference of PAA.MTBD and MWT and RAC in all experimental groups had significance(P<0.05).The VEGF expression was positive on the endothelial cell.The general tendency of VEGF expression intensity from stronger to weaker was RA Control,Normal Control,CDH RA and CDH NS.And the difference of VEGF expression intensity on the sections had statistic significance(P<0.05).The ET expression was positiveon the endothelium celland smooth muscle of pulmonary arterioles,epithelium mucosae and smooth muscle of bronchioles and alveolar epithelium.The general tendency of endothelin expression intensity from stronger to weaker was CDH NS,CHD RA,Normal Control and RA Control.Conclusions 1.The teratogen Nitrofen can produce a congenital diaphragmatic hernia(CDH)with pulmonary development in rodent fetuses that closely parallel observations made in humans.The most of the diaphragmatic hernia exist at left for prenatal intervention Nitrofen on day 9.5 of gestation.2.Retinoic Acid can improve the development of pulmonary in congenital diaphragmatic hernia rat models.It can make the walls of pneumoangiograms and bronchioles thin,and increase vascular lumen to treat pulmonary hypoplasia and pulmonary hypertension.3.Retinoic Acid can make VEGF express up-regulation and ET dowm-regulation in the fetal rat lungs.It is possible that retinoic acid exert its effect through regulate the VEGF and ET's expression in the fetal rat lungs.But the relationship between CDH and VEGF and ET is still not clear.It remains a long way to declare the mechanism of the role of VEGF and ET in CDH.