Effect And Significance Of Tetrandrine On Endothelin Expression In Lungs Of Nitrofen-induced Congenital Diaphragmatic Hernia Rat Models

Objective: To approach the effect of traditional Chinese medicine— Tetrandrine and its significance on endothelin expression in the lungs of the rat models with nitrofen-induced congenital diaphragmatic hernia.Methods: 25 adult feminine Sprague-Dawley rats were divided into 5 groups (5 rats in each group): 1. Normal Control(NC); 2. Congenital Diaphragmatic Hernia Normal Saline(CDH NS); 3. Congenital Diaphragmatic Hernia Dexamethasone(CDH DEX); 4. Congenital Diaphragmatic Hernia Tetrandrine(CDH TET); 5. Congenital Diaphragmatic Hernia Dexamethasone + Tetrandrine(CDH DEX+TET). Each pregant rat of NC group was administered vegetable oil by gavage on day 9.5 of pregnancy. Other group rats were administered a single oral dose 115mg/kg of nitrofen .On day 18.5 of pregnancy, each rat of NC and CDH NS groups was injected 2 ml Normal Saline intraperitoneally. CDH DEX group rats was injected Dexamethasone 0.25mg/kg/d intraperitoneally. CDH TET group rats was administered Tetrandrine 30mg/kg/d by gavage. CDH DEX +TET group rats was injected Dexamethasone 0.25mg/kg/d intraperitoneally and administered Tetrandrine 30mg/kg/d by gavage simultaneously. Pregnant rats were anesthetized with ether on day 21.5 of pregnancy. The fetuses were delivered by cesarean section and executed by decollation. The body weight and lung tissue weight of each fetus were recorded. Lung histologic evaluations and Endothelin immunohistochemistry staining evaluations were performed with image analysis. The expression of Endothelin in the fetal lung tissue was analyzedwith orientation and quantitation. The experimental data were performed with statictical analysis.Results: 5 feminine rats produced 38 fetuses without CDH in the normal control group. 19 feminine rats(l rat was died by intragastric administration in the CDH DEX group)in other four groups produced 126 fetuses with 57 CDH(Abnormal rate was 45.2%). Lw/Bw of CDH groups were lower than those of normal control group. The difference between groups had statistic significance (P <0.05). Lw/Bw of NS groups in the CDH groups was lower than those of Dex , Tet and Dex+Tet groups. The difference between groups had statistic significance (P <0.01). The difference of Lw/Bw between DEX , TET and DEX+TET groups 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 thickness of CDH DEX. CDH TET and CDH DEX+TET groups were between the preceding two groups. The Endothelin expression was positive on the endothelial cell and smooth muscle of pulmonary arterioles, epithelium mucosae and smooth muscle of bronchioles and alveolar epithelium. The expression intensity of pulmonary arteriolar endothelium and bronchiolar epithelium was stronger than that of smooth muscle and pulmonary mesenchymal. The general tendency of endothelin expression intensity from stronger to weaker was CDH NS, CDH DEX, CDH TET, CDH DEX+TET and NORMAL CONTROL groups. Image and statistics analysis manifested the difference of pulmonary arterioles and bronchioles wall thickness between groups had statistic significance (P <0.05). The difference of endothelin expression intensity on the sections, pulmonary arterioles and bronchioles between groups had statistic significance (P <0.05). The wall thickness, the section area of the wall and Endothelin expression intensitybetween the pulmonary arterioles and bronchioles had positive correlation.Conclusion: It is probable that tetrandrine improve the pulmonary hypoplasia markedly in the rat models of nitrofen-induced congenital diaphragmatic hernia. It can make the walls of pneumoangiograms and bronchioles thin and make endothelin express down-regulation in the fetal rat lungs. It is possible that tetrandrine exert its effect through inhibiting synthesis and release of endothelin in the lungs and preventing combination of endothelin and its receptor.