Background:Percutaneous coronary intervention (PCI) causes endothelial damage,resulting in an inflammatory response with elevation of markers such as high-sensitive C-reactive protein (hs-CRP) and vascular cell adhesion molecule-1 (VCAM-1),which are associated with restenosis after PCI.Evidence suggests that microRNA-126 (miR-126) plays an important role in vascular inflammation,but its correlation with PCI-mediated inflammation has not been investigated.In this study,we investigated the effect of PCI on circulating miR-126 and inflammation markers such as hs-CRP and VCAM-1.Methods:We enrolled 130 patients with coronary artery disease (CAD) in the Second Hospital of Jilin University from October 2015 to December 2015.Among them,82 patients with CAD,defined as at least one major epicardial vessel with ＞70％ stenosis who planned to undergo PCI,were divided into acute coronary syndrome (ACS) group (46 patients) and stable angina (SA) group (36 patients).Forty-eight patients confirmed by coronary angiography without PCI were used as controls.The plasmas of all patients were collected prior to PCI and at 30 min,24 h,and 72 h after PCI.The plasma VCAM-1 and hs-CRP were detected by enzyme-linked immunosorbent assay,and the miR-126 was evaluated by quantitative reverse transcription-polymerase chain reaction.Results:Plasma concentrations of hs-CRP and VCAM-1 in patients with either ACS (n =46) or SA (n =36) were significantly higher than in controls (n =48) (P ＜ 0.0l) prior to PCI,and increased further at 24 h and 72 h after PCI,compared with prior PCI.Moreover,VCAM-1 was positively correlated with balloon time and pressure.In contrast,the plasma concentration of miR-126 was significantly lower in patients with CAD than in controls,and further decreased with time post-PCI.A negative correlation was observed between miR-126 and hs-CRP and VCAM-1 at 72 h after PCI.Conclusion:There was a negative correlation ofmiR-126 with the PCI-induced markers of inflammation such as hs-CRP and VCAM-1.