Objective To evaluate the effect of anti-myosin monoclonal antibodies-nuclear factor kappa B (NF-κB) decoy oligodeoxynucleotides-lipofectamine compound (mAb2G4-ODN-lip) on myocardial ischemia-reperfusion (I/R) injury in rats.Methods Forty clean-grade healthy adult male Sprague-Dawley rats,aged 8-10 weeks,weighing 240-260 g,were divided into 4 groups (n=10 each) using a random number table:sham operation group (group S),myocardial I/R group (group I/R),ODN-lip group (group ODN) and mAb2G4-ODN-lip group (group mAb2G4).Myocardial I/R was induced by occlusion of the left anterior descending branch of coronary artery for 30 min followed by 120 min reperfusion.In ODN and mAb2G4 groups,ODN-lip (100 μg ODN) and mAb2G4-ODN-lip (100 μg ODN) compounds were injected via the femoral vein,respectively,immediately after onset of ischemia.The left anterior descending branch of coronary artery was only occluded but not ligated in group S.The animals were sacrificed at 120 min of reperfusion and myocardial specimens of the left ventricle on the ischemic side were obtained for examination of the pathological changes (using haematoxylin and eosin staining) and for determination of the expression of NF-κB (by Western blot) and contents of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) (by enzyme-linked immunosorbent assay).Results Compared with group S,the expression of NF-κB was significantly up-regulated,and the contents of TNF-α and IL-6 were increased in I/R,ODN and mAb2G4 groups (P＜ 0.05).Compared with group I/R,the expression of NF-κB was significantly down-regulated,and the contents of TNF-α and IL-6 were decreased in ODN and mAb2G4 groups (P＜0.05).Compared with group ODN,the expression of NF-κB was significantly down-regulated,and the contents of TNF-α and IL-6 were decreased in group mAb2G4 (P＜0.05).The pathological changes of myocardial tissues were significantly attenuated in group I/R,group ODN and group mAb2G4 in turn.Conclusion mAb2G4-ODN-lip can mitigate myocardial I/R injury in rats.