ABSTRACT
BACKGROUND: Experimental studies of vascular remodeling in the pulmonary arteries have been performed actively. These models required a persistent vascular insult for intimal injury induced by chronic hypoxia, monocrotaline intoxication or chronic air embolism and characterized medial hypertrophy and neointimal formation by active synthesis of the extracellular matrix protein. The purpose of this study was to determine the pattern of pulmonary vascular remodeling after obstruction of the pulmonary vein. MATERIAL AND METHOD: Obstruction of the right pulmonary vein with a metal clip was performed in Sprague-Dawley rats (352+/-18 g, n=10) to cause pulmonary vascular disease. Fifteen days later, experimental studies were done and finally the both lungs and hearts were extirpated for experimental measurement. Pulmonary arterial pressure, weight ratio of right ventricle (RV) to left ventricle (LV) and ventricular septum (S) (RV/LV+S weight ratio), and pulmonary artery morphology (percent wall thickness, %WT) were evaluated and compared with normal control groups. RESULT: Pulmonary hypertension (38+/-12 mmHg vs 13+/-4 mmHg; p<0.05) and right ventricular hypertrophy (right ventricular/left ventricular and septal weight ratio, 0.52+/-0.07 vs 0.35+/-0.04; p<0.05) with hypertrophy of the muscular layer of the pulmonary arterial wall (percent wall thickness, 22.4+/-6.7% vs 6.7+/-3.4%; p<0.05) were developed by 15 days after obstruction of the pulmonary vein. CONCLUSION: Obstruction of the pulmonary vein developed elevation of pulmonary blood pressure and medial hypertrophy of the pulmonary artery. These results are a part of the characteristic vascular remodeling. Theses results demonstrate that obstruction of the pulmonary vein can develope not only high pulmoanry blood flow of contralateral lung but also intima injury inducing vascular remodeling.