Objective To observe the effect of simvastatin on vessel smooth muscle cell proliferation and the changes of P27kip1 express and proliferating cell nuclear antigen(PCNA) after stenting in abdominal aorta of rabbits.Methods Forty-five male New Zealand white rabbits were allocated into three groups: normal group(n=15) was on normal diet;control group(n=15) was on 1.5% high cholesterol diet and underwent denudation injury of abdominal aorta with balloon from femoral approach and a stent was implanted at stenosis segment when more than 50% stenosis had formed angiographically;treatment group(n=15) was given simvastatin 5 mg/d after stenting,and other treatments were the same as control group.Rabbits were killed on the 30th day after stenting,stented abdominal aorta and proliferated neointima in stent was harvested.The histological changes of abdominal aorta was observed;the expression of P27kip1,Smooth muscle cell α-actin and PCNA in each group was analyzed.Results (1) The histomorphologic results showed that the neointima was mainly composed of smooth muscle cells after stenting.There was a great difference of the thinkness of vessel wall of neointima and the neointimial area between the treatment group and control group;(2)The expression of α-actin in treating group was significantly decreased when comparing to normal group and control group;(3)Compared with control group,the expression of P27kip1 in the neointima VSMC cell nuclear increased(P<0.
01);and the expression of PCNA decreased(P<0.01).(Conclusion (1) The atherosclerosis and stenosis model with rabbits has been successfully established) by balloon de-endotheliazation plus cholesterol diet;(2) The results of ultrasonic Doppler are accordant with angiography for the stenosis evaluation of abdominal aorta;(3) Simvastatin could decrease the expression of α-actin and the thickness of hyperplastic neointima;The mechanism involved in this process may be related with the increasement of P27kip1 protein expression and the decreasement of PCNA expression in the neointima VSMC cell nuclear.It is supposed that simvastatin may suppress the proliferation of VSMC and the neointima hyperplasia through up-regulating of the expression of P27kip1 and down-regulation of expression of PCNA in the neointima.