The Research Of Enalapril On Pulmonary Hypertension And Pulmonary Vascular Structural Remodeling Induced By High Pulmonary Blood Flow In Rats

Objectives: to explore the influence of high pulmonary blood flow on pulmonary hypertension, pulmonary vascular structural remodeling and the therapeutic mechanism and effect of ACEI on pulmonary hypertension and pulmonary vascular structural remodeling induced by high pulmonary blood flow in rats.Methods: 23 male SD rats were randomly divided into control group, shunting group, and shunting with enalapril group. Abdominal aorta and inferior vena cava shunting were produced in rats of shunting group and shunting with enalapril group. After 11-week shunting, pulmonary artery mean pressure(mPAP) of each rat was measured by using a right cardiac catheterization procedure. The ratio of right ventricular mass to body weight (RV/BW) and the ratio of right ventricular mass to left ventricular plus septal mass (RV/LV+S) were documented. Pulmonary vascular microstructure was measured. The ratio of vascular wall thickness/vascular external diameter (WT%) and the ratio of vascular wall area/total vascular area (WA%) were documented. Meanwhile, angiotensinII (AngII) contents of lung tissue was measured by radioimmunoassay. The concentration of plasma nitric oxide (NO) was measured by spectrophotometry. The expressions of vascular endothelial growth factor (VEGF) by pulmonary arteries were semiquantitative by immunohistochemistry and image analysis.Results: 1. After 11-week aortocaval shunting, mPAP, RV/BW and RV/LV+S were significantly increased in shunt rats as compared with those of normal controls respectively. Muscularization of small pulmonary artery, WT% and WA% of pulmonary muscularized arteries were obviously increased in shunt rats compared with controls. Meanwhile, in the lung tissue, Angll contents also increased significantly, and VEGF protein expressionssignificantly increased in endothelial cells and smooth muscle cells of the pulmonary artery in rats of shunting group than that in control group . 2. However, mPAP, RV/BW and RV/LV+S were significantly decreased in rats of shunting with enalapril group as compared with shunt rats respectively. WT% and WA% of pulmonary muscularized arteries were obviously decreased in rats of shunting with enalapril group compared with shunt rats respectively. Meanwhile, plasma NO concentration were significantly increased, VEGF protein expressions reduced in endothelial cells of the pulmonary artery in rats of shunting with enalapril group than that in shunting group.Conclusions: It is feasible to establish a rat model of pulmonary hypertension via an aortocaval shunting processure. Enalapril might ameliorate pulmonary hypertension and pulmonary vascular structure remodeling induced by high pulmonary blood flow.