Effect of adenovirus-mediated local tissue factor pathway inhibitor gene transfer on thrombosis formation in rabbit carotid artery injuries

Abstract

Objective To observe the effects of tissue factor pathway inhibitor(TFPI) on thrombosis formation in rabbit carotid arteries after ballon injury. Methods Fouty rabbits with the weight 2.5-3.0 kg were respectively divided into 4 groups, Ad-TFPI, Ad-LacZ, PBS and normal control groups. The normal control group was not given any treatment and other 3 groups were given 0.2 ml Ad-TFPI, Ad-LacZ or PBS reproduced by the Dispatch catheter respectively after the PTCA balloon iniury on the right carotid arteries. Ten days after gene transfer the repeated balloon injury was performed in the 3 groups, and the first balloon injury was performed in the normal control group by the same method. The carotid blood flow was recovered immediately after the injury. Thirty minutes later all the animals were sacrificed. The injured carotid arteries and one part of contralateral normal artery were cut down, scissored along the long axis, flattened and fixed in the 2% glutaral. The platelet aggregation and thrombosis formation on the luminal surfaces was observed under electron microscope. Results The electron microscope results showed that the vascular endothelial cell structure was integrated and lined up in order in the nomal artery which had no any injury. After the balloon injury in the normal control group, the structure of the endothelial cell was disintegrated, and there was some platelet aggregation but no fibrosis formation. A large amount of platelet aggregated but no fibrosis formed in Ad-TFPI group after the repeated balloon injury. A large amount of fibrosis formed and red cells piled up in the Ad-LacZ and PBS group. The positive rate of thrombosis formation among groups had siginificant differences(χ2=14.95, P 0.05). The positive rate in Ad-LacZ group(80%) was higher than in the normal control group(10%, χ2=9.90, P 0.05). The positive rate in PBS group(70%) was higher than that in the normal control group(10%, χ2=7.50, P< 0.01). Conclusions The repeated balloon injury method can cause a large amount of fibrosis formation in the rabbit carotid. TFPI gene inhibits thrombosis formation in balloon-injured rabbit carotid arteries. Key words: Tissue factor pathway inhibitor; Gene therapy; Carotid artery injuries; Thrombosis formation; Microscopy; electron; scanning