Abstract: Objective: The purpose of this study was to determine the effects of Sirolimus-eluting stents on the expression of the TNF-alpha and the mechanism of Sirolimus-eluting stents implantation for prevention of in-stent restenosis. Methods: Fourteen male miniature porcine were randomized (seven animals per group) to receive either bare-metal stents or sirolimus-eluting stents. The stented-coronary arteries were harvested at 4 weeks after stent implantation and Serial peripheral blood samples were obtained before stent implantation , at 1 and 4 weeks after the implantation. Reverse transcription polymerase chain reaction (RT-PCR) method was taken to detect the expression of TNF-alpha mRNA. The level of tumor necrosis factor-alpha (TNF-alpha) in serum were assessed by enzyme-linked immunosorbent assay (ELISA). Results: TNF-alpha serum levels in Sirolimus-eluting stents group did not differ before stent implantatio，at 1 and 4 weeks after the implantation. In bare-metal stents group, TNF-alpha serum levels increased gradually, especially TNF-alpha serum levels at 4 weeks after stent implantation enhanced significantly compared with before stent implantation. TNF-alpha serum levels before stent implantation and at 1 weeks did not differ between both groups, whereas TNF-alpha serum levels at 4 weeks after stent implantation is significantly higher in bare-metal stents group. The RT-PCR analysis revealed an reduced expression of TNF-alpha mRNA in the Sirolimus-eluting stents group than in the bare-metal stents group. Conclusions: Sirolimus-eluting stents can inhibit the expression of the TNF-alpha mRNA and strut-associated inflammatory response in the porcine coronary model.

Key words: TNF-alpha , Sirolimus-eluting stents , In-stent restenosis