目的:研究犬急性心房颤动(房颤)时心房内皮细胞尿激酶型纤溶酶原激活物(u-PA)蛋白表达的变化,探讨房颤时心房附壁血栓形成的可能机制.方法:取12只健康成年杂种犬,随机分为两组:快速心房起搏(RAP)组(6只):建立犬急性房颤动物模型；正常对照组(6只):仅给予开胸,不进行起搏.分别取两组犬的左心耳、右心耳部位心肌组织,应用免疫组织化学技术检测心耳内皮细胞u-PA蛋白表达的改变.结果:(1) RAP组所有犬均可诱发出阵发性房颤；(2) RAP组犬心耳内皮细胞均未见u PA蛋白表达,正常对照组u-PA蛋白表达阳性率为75.0％,RAP组u-PA蛋白阳性率显著低于正常对照组的(P＜0.001).结论:急性房颤时心耳内皮细胞尿激酶型纤溶酶原激活物水平下降,提示在房颤早期内皮细胞纤溶储备功能降低,这可能与房颤时附壁血栓形成有关.%Objective: To investigate change of expression of urokinase-type plasminogen activator (u-PA) in atrial endothelial cells in dogs with acute atrial fibrillation (AF), and study the possible mechanism of formation of atrial ? Mural thrombosis during AF. Methods: A total of 12 healthy adult dogs were randomly divided into rapid atrial pacing group (RAP group, n= 6, established acute AF model with rapid atrial pacing) and normal control group (n = 6, only received thoracotomy without pacing). Immunohistochemistry was used to detect change of u-PA expression in endothelial cells from left and right auricular appendages of the dogs. Results: (1) Paroxysmal AF was induced in all dogs in RAP group; (2) No u-PA expression was observed in endothelial cells of auricular appendages in RAP group while positive rate of u-PA was 75. 0% in normal control group, positive rate of u-PA in RAP group was significantly lower than that of normal control group (P<0. 001). Conclusion: Level of urokinase- type plasminogen activator decreases in endothelial cells of auricular appendage during acute atrial fibrillation, suggesting that endothelial fibrinolytic reserve decrease in early period of atrial fibrillation, which may be related with formation of mural thrombosis during atrial fibrillation.
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