Evaluation Of The Significance Of Dynamic Changes Of D-Dimer And Fibrinogen In Rats Model Of Deep Vein Thrombosis Combined With Venography

Objective To establish SD rats model of deep vein thrombosis, and evaluate the significance of the dynamic changes of D- dimer and fibrinogen in rats before and after modeling operation with combination of inferior vena cava venography.Methods A total of 28 SD rats were divided randomly into the model group(n=23) and control group(n=5). For the model group, the infrarenal portion of inferior vena cava was exposed through a midline laparotomy, venous thrombosis was induced in the inferior vena cava in a surgical procedure, which involved a combination of blocked blood flow after ligation and endothelial damage with the application of microvascμlar clip. The control group was just exposed the inferior vena cava through a laparotomy without ligation and forceps clip. Blood samples were collected respectively 1 day before operation and postoperative 1, 4, 7, 10, 14, 21 days. Quantification of fibrin and D- dimer were tested by ELISA after the blood sample centrifuged. Venography was also performed to observe the changes of thrombus and condition of vascμlar recanalization in model rats.Resμlts Both the model group(n=17) and control group(n=5) survived during the whole experiment. The differences of fibrinogen and D- dimer in rats before and after surgery were statistically significant in both groups. And the content of fibrinogen and D- dimer was significantly higher than the preoperative after surgery in both groups, Fibrinogen and D- dimer recovered to preoperative levels 10 days after surgery in control group while 21 days in the model group. Furthermore, there was no significant difference between two groups. Thrombus length changes with time in a curve of parabola, almost completely dissolving after 21 days.Conclusion Abnormal increased of fibrinogen and D- dimer can be caused by surgical trauma. Venography through the rat caudal vein is a new method to observe the changes in inferior vena cava thrombus. While increased fibrinogen and D- dimer have higher sensitivity in the diagnosis of acute deep vein thrombosis; Fibrinogen had important reference value in the evaluation of thrombus changes, but D- dimer lacked specificity in this aspect.