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<0.01). The positive rate in Ad-TFPI group(20%) was lower than that in Ad-LacZ group(80%, χ2=7.20, P<0.01) and PBS group(70%, χ2=5.05, P<0.05), but was higher than that in the normal control group(10%, χ2=0.39, P>0.05). The positive rate in Ad-LacZ group(80%) was higher than in the normal control group(10%, χ2=9.90, P<0.01) and in the PBS group(70%, χ2=0.27, 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.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the in vivo gene expression of adenovirus-mediated human tissue factor pathway inhibitor (hTFPI) and its inhibition effects on intimal proliferation in rabbit carotid arteries after balloon injury.</p><p><b>METHODS</b>Rabbits underwent carotid artery balloon injuries were treated with Ad-TFPI (n = 25), Ad-LacZ (n = 25) or PBS (n = 10), respectively. Sham operated rabbits (n = 10) serve as normal controls. The expressions of human TFPI at mRNA and protein levels were detected by RT-PCR and ELISA respectively on the 3rd, 7th, 10th, 14th, 28th day after operation. Intimal proliferation was detected by angiograms and morphometric analysis.</p><p><b>RESULTS</b>TFPI mRNA and protein expressions were detected at 3 days and peaked at the 10th and 14th day after TFPI gene transfer. The expressions were still detectable on the 28th day. There was no TFPI expression in Ad-LacZ group. The carotid angiogram results indicated that the minimal lumen diameter in TFPI group was significantly larger and the lumina stenosis percentage was significantly lower in TFPI group compared those in Ad-LacZ and PBS groups (all P < 0.05). The morphometric analysis showed that the intimal area, the ratio of the intimal/media area, the lumina stenosis percentage in TFPI group were all significantly reduced compared with those in Ad-LacZ and PBS groups (all P < 0.01).</p><p><b>CONCLUSIONS</b>The TFPI gene could be effectively transferred by adenovirus vector to injured carotid arteries and transferred Ad-TFPI could significantly attenuate intimal proliferation in balloon injured carotid arteries in rabbits.</p>