Aim To investigate the effect of atorvastatin on intimal hyperplasia of carotid artery after adventitia removal in spontaneously hypertensive rats (SHR). Methods Thirteen-week-old male SHR(n=24) removed right carotid artery adventitia were randomized into three groups(n=8,each): SHR group,atorvastatin group and valsartan group.8 age-matched male Wistar-Kyoto rats were selected as the normal control group(WKY group).Plasma and carotid artery angiotensinⅡ(AngⅡ) levels were measured by radioimmunoassay.Lumen cross section area(LA),intraelastic layer area(IELA) and extraelastic layer area(EELA) were measured by computed video processing,and the ratio of(IELA-LA)/(EELA-IELA) was calculated.The expression of angiotensin converting enzyme-2(ACE-2) protein was determined by immunohistochemistry method.The expression of ACE-2 mRNA was evaluated by reverse transcription-polymerase chain reaction(RT-PCR). Results Compared with adventitia integrity,the intimal hyperplasia in adventitia removal was exacerbated significantly(p<0.01),and it was markedly inhibited both in atorvastatin and valsartan group(all p<0.01).Carotid artery AngⅡ level in adventitia removal was significantly higher than that in adventitia integrity(p<0.01),while the expression of ACE-2 mRNA and protein in adventitia removal was markedly lower than that in adventitia integrity(p<0.01).Compared with SHR group,carotid artery AngⅡ level in atorvastatin group were reduced significantly(p<0.01),whereas plasma AngⅡ level,the expression of ACE-2 mRNA and protein were increased markedly(all p<0.01). Conclusions Intimal hyperplasia in carotid artery after adventitia removal in SHR is markedly reversed by atorvastatin,which may be related to local ACE-2 up-regulation.