Abstract: Objective To investigate the effect of astragalus membranaceus on angiotensin II (AngII) induced vascular remodeling in mice and its underlying mechanism. Methods Mice were randomly divided into 4 groups (n=10/group) including control group, AngII group, AngII+Losartan group and AngII+Astragalus group. In control group, mice were given 0.2 ml/d normal saline by gastric gavage. In the other 3 groups, mice were given 200 ng/(kg?min) AngII by an osmotic pump embedded subcutaneously. In addition, in AngII+Losartan group, mice were given 10 mg/(kg?d) Losartan by gastric gavage; in AngII+Astragalus group, mice were given 20 g/(kg?d) by gastric gavage. All the mice were treated for 14 days. Systolic pressure was measured by the tail-cuff method every 2 days. Mice were sacrificed on day 14 and aortas were collected. HE and Masson’s staining were performed to observe vascular remodeling. RT-PCR was carried out to detect transcriptional expression of collagen I. Western Blot was performed to detect expression of angiotensin converting enzyme 2 (ACE2) and angiotensin II type 1 receptor (AT1R). Results Administration of astragalus membranaceus significantly decreased AngII induced blood pressure elevation (P<0.05), attenuated thickening and fibrosis of aorta, decreased mRNA level of collagen I (P<0.05), up-regulated ACE2 expression (P<0.05) and down-regulated AT1R expression (P<0.05). Conclusion Astragalus membranaceus alleviates vascular remodeling induced by AngII in mice, possibly through up-regulating expression of ACE2 and down-regulating AT1R.

Key words: angiotensin II, vascular remodeling, fibrosis, astragalus membranaceus