Impact And Significance Of Sildenafil On The Fetal Lung Expression Of PAI-1、 VEGFA、HIF-2a、PDE5 In A Rat Model With Congenital Diaphragmatic Hernia

Objective: The pathogenesis of congenital diaphragmatic hernia( CDH) lung development and pulmonary artery hypertension remains unclear. Interactions between the expression of plasminogen activator inhibitor-1(PAI-1)、vascular endothelial growth factor A(VEGFA)、hypoxia-inducible factors 2alpha(HIF-2a) and phosphodiesterases-5(PDE5) in the fetal lung development need to be studied clearly.In this study,we aimed to explain the relationship between these factors,and to examine the effects of antenatal sildenafil on the pulmonary vascular development in an CDH model.Methods: The successful breeding of adult female SD rats were randomly divided into 4 groups.At gestational day 9.5,each of the rat fetuses in group 1 and 2 was given Nitrofen 125 mg in 1ml olive oil by gavage, the group 3 and 4 were given the same amount of olive oil. Gestational day 11.5 to 20.5d, everyday fetals in group 2 and 4 were given sildenafil 8mg dissolved in 2ml of olive oil by gavage, group 1 and 3 were given the same amount of olive oil. Gestational day 21, after anesthesia with pentobarbital sodium, the pregnant mice underwent cesarean section and produced fetal rats. Thoracotomy completely removal of both sides of the lung, 4 times the magnifying glass observation with or without diaphragmatic defect, record the fetal rat lung weight, diaphragmatic hernia position and size one by one. The lung tissue under H&E staining, were measured and recorded of MWT, MA. The expression of PAI-1, VEGFA, HIF-2a, PDE5 were observed by immunohistochemical stain, the data were statistically analyzed..Results: The CDH model was successfully established with nitrofen-induced. The fetal diaphragmatic hernia formation rate were 72.41% at the group 1 and 60.53% at the group 2 respectively, the difference was not statistically significant(p=0.31). The CDH of modle decreased lung to body weight ratio: 19.96±4.52(CDH)vs 29.85±6.16(control)(p<0.001), The CDH of modle intervening by sildenafil increased lung to body weight ratio 20.28±3.89(CDH sildenafil)vs 19.96±4.52(CDH placebo)(p=0.76). The CDH of modleincreased media wall thickness(MWT)33.64±8.49(CDH)vs 17.62 ± 5.21(control)( p<0.001), the CDH of modle intervening by sildenafil decreased MWT 27.34±7.65(CDH sildenafil)vs33.64 ± 8.49(CDH placebo)( p<0.001).CDH increased media section area(MA%) 86.16±6.90(CDH)vs 69.10±6.61(control)(p<0.001), sildenafil decreased MA% 74.85±13.16(CDH sildenafil) vs 86.16±6.90(CDH placebo)(p<0.001). CDH may decrease PAI-1, HIF-2a, VEGFA expression while sildenafil increase PAI-1, HIF-2a, VEGFA expression significantly.Sildenafil made the expression of PDE-5 reduced, the difference was statistically significant.Conclusion: The congenital diaphragmatic hernia rat animal model induced with nitrofen can well simulate the pathological changes of pulmonary hypoplasia of diaphragmatic hernia. Antenatal sildenafil on diaphragmatic hernia induced rate had no significant effect, but could reduce diaphragmatic hernia vascular medial wall thickness and lung arteriole muscularization of the rat animal model. In the CDH group,PAI-1, HIF-2a, VEGFA expression decreased while antenatal sildenafil elevated in the lung tissues of the fetal rat.PAI-1, HIF-2a and VEGFA may promote fetal lung angiogenesis and reduce the pathological changes of pulmonary arterial hypertension.