Objective To investigate the inhibitory effect of suppressor of cytokine signaling3 (SOCS3) on the pro-inflammation of platelet-derived growth factor-BB (PDGF-BB)-induced vascular smooth muscle cells (VSMCs).Methods The recombinant adenovirus vector containing rat SOCS3 gene was transfected into VSMCs induced by PDGF-BB.After 24 h,real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were used to analyse the mRNA and protein expression of SOCS3,signal transducer and activators of transcription 3 (STAT3) ( only by Western blotting),P-STAT3 ( only by Western blotting),interleukin (IL) -1 β,IL-6,tumor necrosis factor (TNF) -α,monocyte chemoattractant protein (MCP)-1 and intercellular adhesion molecule-1 (ICAM-1).Results The expression levels of SOCS3 mRNA and protein,STAT3 protein,P-STAT3 protein,IL-1 β,IL-6,TNF-α,MCP-1 and ICAM-1 were significantly up-regulated in VSMCs induced by PDGF-BB.However,after VSMCs were transfected with pYrAd-rSOCS3 and treated with PDGF-BB,the expression of SOCS3 mRNA and protein was further up-regulated,and that of STAT3 protein,P-STAT3 protein,IL-1 β,IL-6,TNF-α,MCP-1 and ICAM-1 was significantly down-regulated.Conclusion In VSMCs,up-regulated SOCS3 may inhibit proinflammatory effect of VSMCs by blocking STAT3 activation and phosphorylation through negatively regulating JAK-STAT3 signaling pathway.These results can provide a novel idea for clinical treatment of vascular proliferation diseases. Key words: Suppressor of cytokine signaling3; Inflammatory cytokine; Vascular smooth muscle cells; Coronary artery disease