SD Rats With Different Blood Flow Status In The Femoral Vein And Their Infrared Thermal Imaging Expression Characteristics

Part Ⅰ.Construction of a rat model of slow blood flow and its infrared thermal imaging expression characteristics Objective:The aim of this study was to establish a rat model of slow blood flow and to explore the corresponding infrared thermal imaging(IRTI)expression characteristics to provide a theoretical basis for the diagnosis of early deep vein thrombosis.Materials and methods:Twelve SD rats were selected and randomly divided into two groups: epinephrine group and saline group(blank control group).The adrenaline group was injected with1 mg/ml of adrenaline each time,and the blank control group was injected with the same amount of saline twice in total.2 h after the first injection,the rats were placed in ice water and swam for 5 min.IRTI was used to collect the temperature of the femoral triangle region on both sides of the rats before and after modeling,and pressurized ultrasound was used to observe whether there was thrombosis in the femoral vein on both sides.After the modeling was completed,blood was collected from the abdominal aorta to detect blood rheology,blood coagulation index and IL-6,and the right femoral vein was taken for HE staining and NF-κB p65 immunohistochemistry.Results:1.The whole blood viscosity low cut(P=0.024)and plasma viscosity(P=0.004)were higher in the epinephrine group than in the saline group;the activated partial thromboplastin time APTT(P=0.001476)and thrombin time TT(P=0.0037)were significantly shorter in the epinephrine group than in the saline group;the IL-6 level was higher than in the saline group(P=0.02).2.Ultrasound examination of both groups of rats indicated that no definite thrombosis was seen in the femoral vein;the vascular morphology and structure of the femoral vein sections were normal in both groups of rats,and no definite thrombosis was seen;immunohistochemistry NF-κB p65 showed definite positive expression,and the mean optical density value(IOD)was not statistically different.3.The maximum temperature in the femoral triangle of the rats in the epinephrine group was 35.34±0.47 ℃ before modeling and 36.57±0.94 ℃ after modeling,and there was a statistical difference in the temperature of the rats in the epinephrine group before and after modeling(P = 0.000267);the maximum temperature in the femoral triangle of the rats in the saline group was 35.27±0.59℃before modeling and 35.20±0.60℃ after modeling.There was no statistical difference in the temperature before and after modeling in the saline group(P=0.292).Conclusions:A model of slow blood flow can be successfully constructed by repeated subcutaneous injection of epinephrine and ice water swimming in rats.The altered blood rheology reflected by increased whole blood viscosity and plasma viscosity and the hypercoagulable state of blood reflected by shortened APTT and TT confirmed that rats in the epinephrine group were currently in a slow blood flow state.After the successful construction of the slow blood flow model,the infrared thermal imaging expression was characterized as abnormally high temperature compared to the saline group,which was associated with increased thermal radiation due to slow blood flow.Part Ⅱ: Characterization of blood flow stagnation in rats and its expression by infrared thermal imagingObjective:In this study,we caused local blood flow stagnation by ligating one femoral vein,observed a series of pathophysiological changes and venous thrombosis after blood flow stagnation,and observed the infrared expression characteristics at different time points by infrared thermal imaging to provide an experimental basis for the early detection and application of infrared on DVT.Materials and methods:24 SD rats were selected and randomly divided into two groups: 18 rats in the ligation group(group divided into ligation modeling 6h,25 h and 72h)and 6 rats in the sham-operated group.The ligated group was modeled by ligating the right femoral vein,and the left side was treated with simple sham surgery without ligating the femoral vein.In the sham-operated group,sham-operated treatment was performed on both sides.Infrared thermal imaging was used to collect the temperature of the femoral triangle on both sides of the rats before modeling,immediately after modeling and at each observation time point,and pressurized ultrasound was used to observe whether there was thrombosis in the femoral vein on both sides.Blood was collected from the abdominal aorta after the final observation time point to detect blood rheology,blood coagulation index and IL-6,and the right femoral vein was taken for HE staining and NF-κB p65 immunohistochemistry.Results:1.Ultrasonic CDFI showed interrupted blood flow in the ligated femoral vein,and no clear blood flow signal was seen;no definite thrombosis was seen in the femoral vein.2.Pathological HE staining showed that incomplete thrombosis was seen at 6h,25 h,and 72 h after modeling of the femoral vein on the ligated side,and inflammatory cells were visible within the thrombus,and the rate of thrombosis was higher the longer the time of blood flow stagnation;the sections of the sham-operated group had normal vessel morphology and structure,and no inflammatory cell infiltration was seen in the vessel wall.3.In the ligated group,there was no clear statistical difference in the blood rheology indexes at each observation time point after modeling compared with the sham-operated group;the prothrombin time PT at 6h,25 h and 72 h after modeling was shortened to different degrees compared with the sham-operated group(P < 0.05),especially at 25 h after modeling;the IL-6 level at 6h,25 h and 72 h after modeling was increased to different degrees compared with the sham-operated group(P < 0.05),especially at 25 h after modeling.4.The endothelial cells of venous endothelial cells showed a little brownish-yellow granule staining at 6h,25 h and 72 h after ligation group modeling,but no positive expression was seen in the sham-operated group.The IOD of NF-κB p65 at 6h and 25 h after ligation group modeling was higher than that of the sham-operated group(P < 0.05).5.The early infrared expression characteristics of the rat model of blood flow stagnation:(i)the temperature on both sides was symmetrically distributed before ligation,and the temperature on the ligated side was lower than that on the non-ligated side immediately,2.5 h and 6 h after ligation,and the temperature on the ligated side recovered at 25 and 72 h after ligation,and the temperature on both sides was roughly symmetrically expressed.(ii)When comparing the temperature at each testing time point,the highest temperature was observed at 25 h after ligation,which was statistically different compared with that before ligation(P < 0.05).Conclusions:Ligation of the rat femoral vein alone can lead to shortened prothrombin time PT,mild local and systemic inflammatory responses,progressive DVT,and altered local infrared thermal imaging expression characteristics can be found.