Quantitative analysis of endothelin and nitric oxide synthase in rat model of postobstructive pulmonary vasculopathy.

There is increasing evidence that endothelin (ET) and endothelial nitric oxide synthase (eNOS) may contribute various kinds of pulmonary vascular remodeling, including postobstructive pulmonary vasculopathy (POPV), which resulted from chronic ligation of unilateral pulmonary artery. The aim of this study was to investigate the expression of ET-1, ET-A receptor, ET-B receptor, and eNOS quantitatively in POPV rats. One month after a left thoracotomy with either left main pulmonary artery ligation (ligated group) or no ligation (control group), rat pulmonary arteries and lungs were used for Western blot analysis using specific antibodies against ET-1, ET-A receptor, ET-B receptor, and eNOS. ET-A receptor was more highly expressed in the pulmonary arteries of ligated rats compared to the control. The expression of ET-1, ET-B receptor,and eNOS was not different between ligated and control rats. These findings suggest that ET-A receptor overexpression would play a main role for pulmonary arterial remodeling in POPV rats, whereas eNOS may serve as a compensatory mediator.