Early growth response gene-1 decoy oligonucleotides inhibit vascular smooth muscle cell proliferation and neointimal hyperplasia of autogenous vein graft in rabbits

OBJECTIVES: The excess proliferation of vascular smooth muscle cells (VSMCs) and the development of intimal hyperplasia is a hallmark of vein graft failure. This study aimed to verify that a single intraoperative transfection of early growth response gene-1 (Egr-1) decoy oligonucleotide (ODN) can suppress vein graft proliferation of VSMCs and intimal hyperplasia. METHODS: In a rabbit model, jugular veins were treated with Egr-1 decoy ODN, scrambled decoy ODN, Fugene6, or were left untreated, then grafted to the carotid artery. The vein graft samples were obtained 48 h, 1, 2 or 3 weeks after surgery. The thickness of the intima and intima/media ratio in the grafts was analysed by haematoxylin-eosin (HE) staining. The expression of the Egr-1 decoy ODN transfected in the vein was analysed using fluorescent microscopy. Egr-1 mRNA was measured using reverse transcription-polymerase chain reaction. The expression of Egr-1 protein was analysed by Western blot and immunohistochemistry. RESULTS: Transfection efficiency of the ODN was confirmed by 4', 6-diamidino-2-phenylindole staining. In the grafts treated with Egr-1 decoy ODN, our study achieved statistically significant inhibition of intimal hyperplasia by ∼58% at 3 weeks. Transfection of Egr-1 decoy ODNs decreased the protein expression of Egr-1 and Egr-1 mRNA. CONCLUSIONS: We confirmed that gene therapy using in vivo transfection of an Egr-1 decoy ODN significantly inhibits proliferation of VSMC and intimal hyperplasia of vein grafts in a rabbit model.