新型大鼠下腔静脉血栓模型的建立及血栓溶解演变过程研究

Reproduction of a new inferior vena cava thrombosis model and study of the evolutionary process of thrombolysis in rats

目的探讨一种新的大鼠下腔静脉血栓模型建立方法,并动态研究静脉血栓溶解的自然演变过程和相关机制。方法 SD大鼠48只随机分为实验组和对照组。实验组缩窄下腔静脉管腔面积80%~90%,然后随机分为3组（n=12）：A组结扎左肾静脉以下下腔静脉所有属支并以神经生物夹刺激静脉壁诱导血管内皮损伤;B组联合神经生物钳损伤下腔静脉壁;C组联合结扎下腔静脉所有属支。对照组（D组,n=12）为假手术组,仅游离而不缩窄下腔静脉。术后比较各组静脉血栓的长度、重量和管腔面积百分比,确定下腔静脉血栓动物模型的最佳建模方式。另取大鼠30只,按最佳方式建模,术后行下腔静脉造影及血栓HE和Masson染色、ED-1免疫组化染色,动态分析静脉血栓溶解的自然演变过程及参与此过程的细胞类型。结果大体观察结果显示A、B、C组均成功诱导血栓形成,A组血栓长度及重量明显高于B、C组（P〈0.01）,而B、C组间比较无明显差异（P〉0.05）,D组无血栓形成。A组静脉血栓占下腔静脉管腔面积明显大于B、C组（P〈0.01）,确定A组为最佳动物模型组。最佳模型组血栓HE和Masson染色结果显示,随时间推移,血栓溶解过程中新生毛细血管逐渐增多,胶原纤维及细胞外基质成分含量逐渐增加;ED-1染色结果显示血栓溶解过程伴有大量巨噬细胞浸润;静脉造影结果表明下腔静脉血栓自然溶解完全再通需3~4周。结论采用缩窄下腔静脉管腔联合结扎静脉属支并损伤血管壁法诱导形成的大鼠下腔静脉血栓与人类深静脉血栓近似,可作为建立深静脉血栓动物模型的首选方法。大鼠下腔静脉血栓的自然溶解演变过程伴随血管新生,而巨噬细胞在此过程中具有重要作用。

Objective To investigate the reproduction of a new model of thrombosis of inferior vena cava （IVC）, and explore the natural process of thrombolysis and its mechanism in rats. Methods Forty-eight SD rats were randomly classified into experimental group and control group. In the experimental group, the lumen of the vena cava was blocked by about 80%-90% with a ligature of IVC below the left renal vein, and then the animals were redivided into three subgroups （n=12, each）. In group A, the IVC endothelium was damaged and its tributaries were ligated. In group B, the IVC endothelium was damaged and its tributaries were not ligated. In group C, no damage was done to the endothelium of the IVC but all its tributaries were ligated. A sham-operated group served as control. The length and weight of the vinous thrombus and the percentage of the IVC luminal area were compared after operation to determine the optimum animal model of venous thrombosis. According to the best mode to establish the model, the thrombus specimens were collected and detected by HE and Masson staining, and the ED-1 expressions were examined by immunohistochemical staining after thrombus formation in 30 rats. The natural evolution of intravenous thrombolysis was analyzed dynamically and the cell types involved in this process were observed. Results Gross observation showed that the experimental group was successfully induced thrombus formation. The thrombus length and weight in group A was significantly higher than thatin group B and group C, and no difference between group B and C. The thrombus area in group A was significantly higher than that in groups B and group C, which identified the group A was the optimal model group of venous thrombosis. In the group reproduced by the best mode of the model, HE and Masson staining results showed that new capillaries and the components of collagen and extracellular matrix increased gradually with the passage of time in the process of thrombus resolution. ED-1 staining indicated a massive infiltration with macrophages during the thrombus resolution. The results of inferior vena cavography showed that natural resolution of the IVC thrombus and complete revascularization needed 3 or 4 weeks. Conclusions The morphological changes in venous thrombus induced by narrow lumen combined with ligation and vessel injury of the IVC in rats are similar to those in human being, which could be a preferred method to establish animal model of deep venous thrombosis. The evolution of natural thrombus resolution comprises angiogenesis and the macrophages play an important role in this process.