Objective: To explore the effect and mechanism of the active fraction of Simiao Yongan Tang (AFSM) on vascular remodeling in hypertensive rats induced by nitric oxide synthase inhibitor (L-NAME). Method: Forty-eight Wistar rats were randomly divided into six groups:AFSM high dose group

medium dose group and low dose group (1

0.5

0.25 g·kg-1·d-1)

captopril group (50 mg·kg-1·d-1)

simvastatin positive drug group (10 mg·kg-1·d-1) and model group. L-NAME was administered to the animals in each group. Their body weight

heart weight

blood pressure and heart rate were determined after four weeks of administration. After sacrificing

their aortic thickness changes were measured through HE staining on aortic root slice. Masson staining was used to observe the changes of the coronary artery fibrosis

and the changes of the expression levels of monocyte macrophage antigen-1 (ED-1) and proliferating cell nuclear antigen (PCNA) were observed by immunohistochemistry method. Result: As compared with the model group

only captopril group could alleviate myocardial hypertrophy; captopril group

AFSM high dose and medium dose groups had certain effects in reducing diastolic and systolic blood pressure; there was no effect on heart rate in various treatment groups; captopril group

AFSM high dose and medium dose groups could significantly reduce the aortic wall thickness; captopril group and AFSM high dose group could significantly reduce the formation of peripheral fibrosis of the coronary artery; captopril group and AFSM high dose group could significantly inhibit the expression levels of ED-1 and PCNA in the coronary artery (P<0.05

P<0.01). Conclusion: The AFSM active fractions can reduce hypertension and improve vascular remodeling. The mechanism may be related to inhibiting the anti-inflammatory effect of ED-1 and the anti-proliferative effect of PCNA.