Experiment Study On Functional And Morphological Change Of The Non-thrombus Vein Segment When Venous Thrombosis Occurred

Objective:To research the functional and morphological influence of experimental rabbits on venous wall in non-thrombus segment caused by vein thrombosis, discuss the possible mechanism of the thrombosis in non-thrombus vein segment. Methods: There are 55 experimental rabbits, which had been divided into 3 groups randomly: Thrombosis group ( Group T, n=25), Sham operation group (Group S, n=25), Normal group (Group N, n=5). The posterior vena cava of Group T were ligated for 48 hours to induce thrombosis model. Group S were opened and closed the venter barely. Collected the sample of double cervical vein at specific points, which are 24 hours, 72 hours, 7 days, 14 days, 28 days after the operation. Observed the expression of t-PA, PAI-1, α-SMA according to immunohistochemical method. The mRNA levels of TF and TFPI were analyzed by semiquantitative RT-PCR. The morphological changes of venous wall were assessed by morphological scanning electron microscopy and transmission electron microscopy. The expression of CD62p and CD63 were detected with flow cytometry. Results: For immunohistochemical result, t-PA had no expression in group N, the expression in group T increased gradually, there were significant difference compared with group S and group N(P<0.05). PAI-1 expressed on low level in group N, the expression in group T. increased gradually, there were significant difference compared with group S and group N(P<0.05). The expression of α-SMA in group T were no significant difference compared with group S and group N(P>0.05). For semiquantitative RT-PCR result,the expression of TF and TFPI mRNA in group T increased by times, which were significant difference compared with group S and group N(P<0.05). Same did group S, which reached the peak on day 7, decreased after that. For electron microscopy result, the injury degree of endothelial cell were aggravated gradually under scanning electron microscopy, reached Ⅱ～Ⅲgrade on day 28,while injury occurred in group S, reached Ⅰ～Ⅱgrade on day 28. Endothelial cell cytoplasm found balloon changes 1 day after under transmission electron microscopy, On day 28 it showed more balloons, loss of endothelial cell, thickening of subendothelial layer. The main indication of group S were balloon in endothelial cell cytoplasm. For flow cytometry result, the expression of CD 62p showed obviously, reached the peak on day 7, decreased after that, which were significant difference compared with group S and group N(P<0.05). The data of CD63 in group T indicated significant difference compared with group S and group N(P<0.05). Conclusions: Endothelial cell on venous wall in non-thrombus segment was in activation status after vein thrombosis. The expression of TF,PAI-1,TFPI,t-PA were increased simultaneously, maintain a high level on day 28, the cause was related with inflammation factors. Vein thrombosis can influence the venous wall in non-thrombus segment, scope limited in theca interna, the main changes was balloon degeneration. The expression of platelet activation increased after vein thrombosis, arrived the peak on day 7, then decreased gradually.