| Objective:To study the thrombolytic efficiency of continuous infusion of microbubbles(MB)and urokinase(UK)with low-intensity ultrasound(LIUS)mediated thrombolysis in vitro.Based on the in vitro experiment,the thrombolytic efficiency of CDT combined with LIUS and MB on the thrombosis of porcine femoral vein was studied with porcine femoral vein thrombosis model established,and the safety of the experiment was evaluated.Materials and methods:1.In-vitro studyWe constructed an in-vitro circulatory model.50 bovine blood clots were divided into 5 groups randomly.In group 1,LIUS combined with continuous perfusion of MB and UK were conducted(continuous perfusion:US+MB+UK).In group 2,LIUS combined with one bolus injection of MB and UK were conducted(one bolus injection:US+MB+UK).In group 3,LIUS combined with continuous perfusion of UK were conducted(continuous perfusion:US+UK).In group 4,LIUS combined with continuous perfusion of MB were conducted(continuous perfusion:US+MB).Group 5 was only given continuously perfusion of UK(continuous perfusion:UK).The thrombolysis rate and dissolved area of bovine blood clots of each group were calculated and analyzed statistically.The erythrocyte structure and the integrity of fibrin net were observed under the microscope.2.In-vivo studyWe established the model of DVT in the hind legs of Bama miniature pigs.16 models of thrombosis were randomly divided into the following two groups for thrombolytic therapy:UT+CDT group:LIUS combined with continuous perfusion of MB and UK through the catheter;CDT group:continuous perfusion of UK through the catheter Intra-catheter constrast-enhanced ultrasound(CEUS)was performed before and after treatment.Vital signs and adverse reactions were closely observed during the experiment After treatment,the animals were sacrificed,and the remained thrombus was taken for pathological examination of porcine fibrinogen HE stained and immunofluorescence staining.Then the erythrocyte structure and the integrity of fibrin net structure was observed.Gross examination of the vascular wall injury and the main branches of pulmonary arteries to reveal any evidence of vascular wall injury and thrombo-embolism.Results:1.Comparison of thrombolysis rate of each group in vitro experimentThe results showed that the thrombolysis rate of each group was different(F=34.837,P<0.01),The thrombolytic rate of group 1 was higher than other groups and the dissolved area was larger than other groups,the difference was statistically significant.(P<0.05).Thrombolysis rate in group 3 and group 5 were higher than group 4(P<0.05).Examinations of HE stained sections showed that the structure of the residue thrombus of group 1 was looser than other group and there were many areas of dissolution.More broken fibrin were observed under immunofluorescence microscope in group 1.2.Evaluation of thrombolysis effect and side effects in vivo experimentCEUS showed that recanalization was achieved in 7 of 8 pigs in the CDT+UT group,and only 2 of 8 pigs in the CDT group.There was statistically significant difference of recanalization rate between the two groups(P=0.041).Examinations of HE stained sections showed that the structure of the residue thrombus of CDT+UT group was looser than CDT group and there were many areas of dissolution in CDT+UT group.More broken fibrin were observed under immunofluorescence microscope in CDT+UT group.There was no injury in the vascular wall and no thrombosis was observed in the main branches of pulmonary artery in both groups.Conclusion:1.In vitro,LIUS combined with MB could enhance the thrombolytic effect of UK;Thrombolysis with continuous injection is more effective than one-bolus injection.2.In the model of DVT of porcine hind legs,LIUS combined with continous perfusion of MB through the catheter can enhance the thrombolytic effect of UK,and no adverse reactions occurred during the experiment which confirmed the effectiveness and safety of this method. |
PDF Full Text Request