Objective:To assess the efficacy, safety and mechanism of self-expanding sirolimus-eluting stent implanted in porcine carotid artery for preventing from early restenosis after angioplasty. Methods:After angioplasty on the dual common carotid arteries by ballon overstretch,6 sirolimus-eluting stents and 6 bare metal stents were implanted in 12 injured carotid arteries of 6 chinese minipigs at random, respectively. Four weeks later,after angiography 6 chinese minipigs were executed. Lumen area,neointimal thickness and area of injured arteries segment were measured by computer image analysis technique. The arteries segment were removed for measurement of the apoptotic index by TUNEL assay and the expression of proliferating cell nuclear antigen(PCNA),Bcl-2 and Bax proteins by immunohistochemistry. Results:Compared with the bare metal stent group,the lumen area of sirolimus group was significantly greater while the neointimal thickness and area was significantly smaller(P < 0.05). PCNA and Bcl-2 expression was significantly decreased in sirolimus-eluting stent group(P < 0.05), while apoptotic index and Bax expression was significantly increased(P < 0.05). Conclusion:Sirolimus-eluting stent can effectively inhibit neointimal formation to prevent early restenosis in porcine common carotid artery 4 weeks after implantation,with the possible mechanism of upregulating the expression of Bax,downregulating the expression of Bcl-2 and inhibiting vascular smooth muscle cell proliferation.