The Experimental Study Of Transcatheter Intra-arterial Thrombolysis In The Treatment Of Severe Frostbite

Background:Frostbite is a cold-induced injury that often occurs in military training activities,and secondly in civil operations in cold areas.Frostbite is divided into mild frostbite??-? degree?and severe frostbite??-? degree?.The tissue damage mechanism of frostbite includes direct damage of cell death caused by early intracellular fluid and external fluid ice crystal formation and indirect injury of tissue ischemia caused by microthrombus formation in the later stage?similar to reperfusion injury?.The traditional treatment of severe frostbite includes early rewarming treatment and surgical amputation lately with high morbidity rate.In recent years,it has been reported that transcatheter intra-arterial thrombolysis can reduce the rate of amputation caused by severe frostbite significantly.Objective:?1?To establish a severe frostbite model of the New Zealand rabbits and conduct experimental observations on hematology,imaging and pathology.?2?To investigate the effectiveness and mechanism of transcatheter intra-arterial infusion of Fufang Danshen Zhusheye in the treatment of severe frostbite.Materials and Methods:?1?Twelve severe frostbite models of the New Zealand rabbits were established by ethanol immersion method.The experiment was observed after routine rewarming treatment.10 severe frostbite models of the New Zealand rabbits were observed on gross and angiography before frostbite,before rewarming after frostbite,0h,6h,12h,24h,2d,3d,4d,5d,6d post rewarming;Venous blood was drawn through the ear vein before frostbite,0h,6h,12h,24h,2d,3d post rewarming to determine WBC,RBC,HGB,HCT,PLT,ALT,AST,BUN,SCR,PT,APTT,FIB by a fully automatic analyzer;Plasma TXB2 and 6-keto-PGF₁? levels were determined by radioimmunoassay,plasma MDA was determined by TBA method,plasma SOD was determined by xanthine oxidase method;the remaining 2 were subjected to pathological examination of affected limbs before frostbite,before rewarming after frostbite,Oh,6h,12h,24h,2d,3d,4d,5d post rewarming.The natural prognosis amputation rate of the severely frostbite model of the New Zealand rabbits was calculated by the toe amputation rate and scoring method.?2?The severe frostbite models of 36 New Zealand rabbits were routinely rewarmed and treated,which were stratified randomly divided into 3 groups,12 models in each group were treated with thrombolytic therapy.Group A:conventional thrombolytic group?t-PA+ heparin+papaverine?;Group B:modified thrombolytic group?t-PA+heparin+papaverine+Fufang Danshen Zhusheye?;group C:control group?normal saline?,angiography and assessment of response was performed on 10 severe frostbite model of the New Zealand rabbits in each group 24 h after thrombolysis,venous blood was drawn through the ear vein 24 h after thrombolysis to determine WBC,RBC,HGB,HCT,PLT,PT,APTT,FIB by a fully automatic analyzer and compared between groups,plasma TXB2 and 6-keto-PGF 1?levels were determined by radioimmunoassay and compared between groups.Plasma MDA were measured by TBA colorimetric method and compared between groups,plasma SOD levels were measured by xanthine oxidase method and compared between groups;the remaining 2 in each group were used for pathological examination of the affected extremities 24 h after thrombolysis;the prognosis amputation of the severe frostbite model of the New Zealand rabbits was analyzed by toe amputation rate and scoring method and compared between groups.Results:?1?The skin color of the affected limbs in the severe frostbite model of the New Zealand rabbits changed from purple blue to pink from Oh to 12 h post rewarming,the degree of swelling gradually increased,angiography showed that the blood flow gradually recovered.From 12 h post rewarming to amputation,the color of the skin changes from pink to purple blue to black at the end and the degree of swelling is reduced,the infusion of the extremities gradually block,the blood flow gradually disappears,and the purple or blue areas of the skin can roughly correspond to the occlusion of the vessels.The white blood cell level of New Zealand rabbits was significantly increased from Oh to 3d post rewarming.The RBC,HGB and HCT trends remained basically the same.The RBC,HGB and HCT levels began to increase at Oh post rewarming and reached a peak at 12 h and recovery to the baseline level before the frostbite at 24h,and decreased at 2d and 3d.The platelet level continued to decrease from Oh to 2d post rewarming,reached the low peak at 24h,and increased at 3d.The ALT,AST,BUN and SCR values were not significantly different from the baseline before frostbite?P>0.05?;6-keto-PGF₁? level continued to increase from Oh to 12h post rewarming,peaked at 12h,began to decrease from 24h to 3d;TXB2 level continued to increase from Oh to 3d post rewarming;MDA level continued to increase from Oh to 3d after warming;the level of SOD continued to increase from Oh to 24h post rewarming and reached the peak at 24h,began to decrease from 2d to 3d.The pathological results of left forelimb of the New Zealand rabbit severe frostbite showed that a large number of vessels dilated or congested and no obvious thrombosis from Oh to 24h post rewarming,mixed thrombus was observed in the vessels from 2d to 5d post rewarming;the final amputation rate was 82.5%and the score was 20.6±3.8.?2?Complete response on angiography in group A,B and C of the New Zealand rabbit severe frostbite model after thrombolytic therapy was 0,3,0 cases,most response were 2,4,0 cases,mild response were 4,2,2 cases,no response in 4,1,8 cases,respectively.There was significant difference in the number of WBCs after thrombolysis between groups?P<0.05?.There was no significant difference in RBC,HGB and HCT?P>0.05?.The number of platelets in group A and B was significantly higher than that in group C?P<0.05?.PT and APTT of group A and group B were significantly longer than group C after treatment with thrombolytic therapy?P<0.05?;FIB of group A and B was significantly lower than that of group C after thrombolytic therapy?P<0.05?.The levels of plasma 6-keto-PGF 1 and SOD in group B were significantly higher than those in group A and C?P<0.05?.The levels of TXB2 and MDA in group B were significantly lower than those in group A and C?P<0.05?.The rate of amputation in group A,B and C was 46.9%,22.5%and 85.0%,respectively.The results of the scoring method were 9.5±2.7,4.3±1.1 and 21.8±4.2,respectively.There were significant differences in the amputation rate and the score method between groups?P<0.05?.Conclusions:?1?Gross,angiographic and pathological observations of severe frostbite in the New Zealand rabbits showed that blood flow of the affected limbs gradually recovered from Oh to 12h post rewarming,thrombus formation at 24 hours post rewarming,vascular gradually occlusion,hematology showed that the blood was in a hypercoagulable state after frostbite and the body developed a severe inflammatory reaction,the PGI2-TXA2 and oxidation-antioxidant system were unbalanced.?2?Fufang Danshen Zhusheye can significantly reduce the amputation rate of the severe model of the New Zealand rabbits,its possible mechanism is that Fufang Danshen Zhusheye can effectively correct the PGI2-TXA2 and oxidation-antioxidation imbalance of the body after severe frostbite.