Construction And Study Of A New Animal Model Of Traumatic Deep Venous Thrombosis In Limbs

Objective: To establish a new animal model of traumatic deep venous thrombosis in limbs and to explore relationship between traumatic deep venous thrombosis(DVT) and pulmonary embolism(PE), this project was carried out as a research basis of traumatic DVT in limbs with orthopedic characteristics.Methods: 1. 120 Wistar rats were divided randomly into fracture, trauma, and control groups. Both lateral proximal thighs of each animal in fracture and trauma groups were damaged (without direct vessel injury) with self-made instrument to different degrees. Then the fixation of spica with plaster bandage was conducted in each group. Gross observation and pathological examinations were performed at different phases after the model being built, the incidences of DVT among the 3 groups were compared with each other and the changes of arterial, endangium, and venous endothelial cell were checked.2. 120 New Zealand white rabbits were divided randomly into 4 groups: fracture, trauma, fixation and control groups. The left part of proximal thigh of each one was damaged with the above instrument (without direct vessel injury) to fracture and trauma groups. The fixation was changed as the joint of left knee and hip flexed in flexible position. In different phases, venous thrombosis and PE were examined with gross observation and histological examination; RBC, WBC, PLT, HB, MID, PT, INR, Fib, TT, APTT and D-Dimer were tested using automatic globulimeter and hemagglutination instrument; MMP-2, CD34 and FVIII-RAg were also measured by immunohistochemistry; thrombosis was also examined by high-frequency color Doppler flow display, DSA, MRA and MRDTI.Results: Both the models of Wistar rats and New Zealand white rabbits were established successfully. In Wistar model, the incidence of deep venous thrombosis in fracture group was 85% at the 7th day after model being built, which was higher than those of trauma and control groups (P<0.05) . There was no arterial thrombosis. However,in the model of NewZealand white rabbits, the incidences of deep venous thrombosis of fracture and trauma groups were 75% and 80% respectively at the 7th day after model being built, which were higher than those of fixation without trauma and controlled blank (P<0.05 ) , and there was no statistical difference between the 2 groups, only a little amount of arterial thrombosis could be found; DVT had a positive correlation with PE (Spearman coefficient correlation is 0.878, PO.05); There were statistical differences between fracture, trauma groups and fixation, control groups, when blood cell components, PT, INR, Fib, TT, APTT, D-Dimer were examined; The deceleration of blood flow of rabbits was detected with the left joints of hip and thigh fixed in flexible position and the inner diameter of venous vessel was reduced correspondently ( P<0.01); The results of DS A and MRA on thrombus detection were same; Thrombosis could be found incompletely by MRDTI ; MMP-2, CD34 and FVIII-RAg were negative.Conclusions: 1. Animal models were designed in simulating the clinical pathology of orthopedics. And the new animal model of traumatic DVT in limbs was established initially and successfully. 2. Our results confirmed that traumatic DVT was associated with the injury of venous endothelial cell, the deceleration of blood flow and the hypercoagulabale state of blood components. 3. The correlation between DVT and PE was explored tentatively, there was a positive correlation between them. 4. Early diagnosis of traumatic DVT with angiography and MRI were compared with each other. It had been proved that MRA was an early and precise method in the diagnosis of traumatic deep venous thrombosis of limbs, and MRDTI could be used as a method of non-invasive for diagnosis, but the technique needs to further improvement. 5. Examined by automatic globulimeter and hemagglutination instrument, indexes of blood cells counting, blood coagulation and fibrinogenolysis could be detected quickly and correctly. 6. The relationship between traumatic inflammatory reaction and thrombosis were studied at molecular level by immunohistochemistry assays. The results of CD34 , MMP-2 and FVIII-RAg were negative. And the possible reasons included : 1) by the way of beating with self-made instrument, fixation and immobilization, the expression of CD34,MMP-2 and FVIII-RAg was not related to DVT; 2) The other possisibility is due to species-specific antibody, this needs to be tested with further experiments. This model could be established easily, the incidence of venous thrombosis was high, and thereproducibility was good.Nevertheless as a reliable model, it is essential to conduct further research on the origin, development and influential factors of traumatic DVT, and it is also important for the studies on prevention and treatment of severe complications such as deep venous thrombosis and pulmonary embolism, etc.