Objective To observe the effects of eluting stents coated with arsenic trioxide(As2O3)and suspended in poly-L-lactic acid(PLLA)on expression of monocyte chemoattractant protein-1 (MCP-1)and interleukin-6(IL-6)and to assess the effects of As2O3 eluting stents on local inflammatory reaction in injured coronary arteries in pigs. Methods Bare metal stents,rapamycin eluting stents and As2O3-eluting stents were randomly and double-blindly implanted into the anterior descending branches,circumflex branches and right coronary arteries in eight pigs.Animals were sacrificed and coronary arteries were isolated 7 days after stents implantation.The expression levels of protein and mRNA of MCP-1 and IL-6 were determined by Western blot analysis and reverse transcription polymerase chain reaction(RT-PCR),and the inflammatory cell infiltration was observed by HE staining and immunohistochemistry. Results Compared to bare metal stents,As2O3-eluting stents and rapamycin-eluting stents identically and markedly inhibited the protein expression level of MCP-1(0.421±0.055 and 0.406±0.042 vs.0.857±0.053,P＜0.01)and IL-6(0.151±0.032 and 0.146±0.051 vs.0.551±0.032,P＜0.01)and correspondingly lowered the mRNA expression level of MCP-1(0.338±0.047 and 0.327±0.051 vs.0.724±0.027,P＜0.01)and IL-6(0.531±0.052 and 0.523±0.061 vs.1.015±0.041,P＜0.01),and significantly reduced the inflammatory cell infiltration of injured coronary arteries in pigs. Conclusions As2O3-eluting stents can effectively inhibit the expressions of MCp-1 and IL-6 and reduce the inflammatory cell infiltration of injured coronary arteries in pigs.