Establishment Of Chronic Deep Venous Thrombosis Model In Canines

Objective: The model of chronic deep vein thrombosis in the lower extremities was established by the method of "femoral vein constricted,inserted an catheter into branch vein and thrombin injected".The evolution of thrombus was observed dynamically,which provided an alternative animal model for the study of chronic venous thrombosis.Methods: 9 adult canines were used for this study.Selected the optional side of the lower limb randomly as the experimental side,the other side as a control.Animal model of iliac vein compression and chronic deep vein thrombosis was simulated,the lateral femoral vein area narrowed 90% by absorbable lines.Catheter was inserted from the branch of the femoral vein at the distal end of the narrowing site,followed by 300 U thrombin injected and then blood flow be blocked for 1h;the catheter was indwelled as a venography pathway.The general conditions of lower limbs of the canines postoperative were observed,which including general situation,such as changes of venous collateral,coagulation function and D-dimer.Thrombosis and collateral veins were evaluated by venography on postoperative day(POD)1,7,14,21,28.And pathological examination was carried out.Result: Model creation was successfully performed in 8out of 9 canines.The model success rate is 88.9%.After that,claudication,increased skin temperature,skin bruising and varicose veins of the affected lower limb were observed in all of them.Leg circumferences at 8 cm above patella reach the maximum on POD 14(p<0.05).The whole process had no necrosis of the lower limbs.D-dimer and fibrinogen detection in dogs were significantly higher than those before operation(p <0.05)at 1,7,14,21 and 28 day postoperative,and significantly higher at 14 day(p <0.05).The level of prothrombin at preoperative was significantly higher than that POD 1,7,14,21 and 28(p <0.05),POD 14 was significantly lower than POD 1,7,21,28(p<0.05).Compared with the control side,experimental side of the venous angiography showed thrombosis;and POD 14 after intravenous angiography shows a very rich side of the vein.HE staining: 1 day after thrombosis showed pale red structure without branch or irregular coral-like platelet trabecular and filled with trabecular fibrin mesh blood cells,platelet trabecular edge attached more neutrophils.28 days after the thrombus showed pulse wall and thrombus boundaries unclear,venous intimal hyperplasia,intimal film filled with fibrous tissue,inflammatory cells and newborn capillaries constitute granulation tissue;thrombus was mechanized,and then pass the state.Conclusion: The model of chronic deep vein thrombosis with reliable,stable,repeatability and so on.At the same time,the catheter hardly be blocked.It could be used for the clinical treatment of chronic venous thrombosis,imaging diagnosis and other aspects of the study.