Abstract: Aim To investigate the effect s of perindopril, an angiotensin converting enzyme inhibitor,on mean pulmonary arterial pressure(mPAP)and pulmonary vascular remodeling.Methods Using the normobaric hypoxia-hypercapnia rat model, the changes of plasma angiotensin Ⅱ(AngⅡ), mPAP and ultrastructure of pulmonary arteriolar wall were observed after administration of perindopril.Results The mPAP and AngⅡ were significantly greater and the ultrastructure of the small lung vessels had a more obvious change in the 4 weeks hypoxia-hypercapnia group than those in the control group.It was also found that perindopril decreased Ang Ⅱ, declined mPAP and amelio rated vascular ultrastructure change.But the change of ultrastructure was similar in the 8 weeks hypoxia-hypercapnia group and perindopril treatment group.Conclusion I t is suggested that chronic hypoxia-hypercapnia should induce the remodeling of pulmonary arteriolar structure via Ang Ⅱ and that perindopril could ease pulmonary vascular remodeling in early stage.

Key words: hypoxia, angiotensin converting enzyme inhibitor, perindopril, pulmonary hypertension