ObjectiveTo evaluate the effect of human heme oxygenase 1 augmentation in vein grafts by adenoviral mediated gene transfer of heme oxygenase 1 (Ad hHO 1) on intimal hyperplasia.MethodsTwenty one Japanese white rabbits were divided into three groups: control group, Ad null control group, and Ad hHO 1 group(each group 7 rabbits). During the operation of rabbits jugular vein into carotid artery interposition grafting, harvested rabbit jugular vein segments were exposed for 30min at room temperature to heparin saline, recombinant replication deficient adenovirus encoding hHO 1(Ad hHO 1, 1× 10 9pfu/ml), and nude recombinant replication deficient adenovirus (Ad null, 1×10 9pfu/ml). Quantitative histological studies of the vein segments were performed 28 days after operation. Protein of hHO 1 was detected with method of immunohistochemical staining(S P) in 14 days and 28 days after operation.ResultsThe average intimal thickness, medial thickness and intimal to medial(I/M) ratio were calculated for each group 28 days after bypass operation. Compared to intimal thickness, I/M ratio of control group veins and Ad null group veins,Ad hHO 1 group veins decreased significantly( P lt;0.01). There was no statistically difference in medial thickness ( P gt;0 05). Strong staining of hHO 1 was detected in vein grafts wall of Ad hHO 1 group.ConclusionAd hHO 1 gene therapy may inhibit intimal hyperplasia of vein grafts in rabbits.