纤维蛋白对肾小球内皮细胞表达纤溶酶原激活物及纤溶酶原激活物抑制物的作用

Effects of fibrin on the expressions of plasminogen activators and plasminogen activators inhibitor in glomerular endothelial cells

目的 观察体外培养人肾小球内皮细胞（ＧＥＣ）表面原位形成的纤维蛋白对 ＧＥＣ表达纤溶酶原激活物及纤溶酶原激活物抑制物（ＰＡ／ＰＡＩ）的影响。方法 应用逆转录聚合酶链反应（ＲＴ－ＰＣＲ）、酶谱分析法与反向酶谱法分别在基因转录水平与蛋白质活性水平上检测纤维蛋白对ＧＥＣ表达ｔＰＡ、ｕＰＡ与ＰＡＩ－１的作用。纤维蛋白平板法检测纤维蛋白对ＧＥＣＰＡ／ＰＡＩ系统的综合效应。结果 纤维蛋白能够明显促进ｔＰＡ、ｕＰＡ与ＰＡＩ－１的ｍＲＮＡ表达上调。无血清ＲＰＭＩ １６４０培养下的ＧＥＣ几乎检测不到ＰＡ活性，但可检测到ＰＡＩ－１的活性。纤维蛋白能够浓度依赖性刺激ＧＥＣ ｔＰＡ与ｕＰＡ活性增加以及ＰＡＩ－１的活性增加，呈浓度依赖性与时间依赖性。相同剂量的纤维蛋白原与纤维蛋白的作用相似。放线菌酮与放线菌素Ｄ均可抑制纤维蛋白上调ＧＥＣ表达ｔＰＡ、ｕＰＡ与ＰＡＩ的作用。纤维蛋白平板法显示，纤维蛋白对ＧＥＣ ＰＡ／ＰＡＩ系统的综合效应是以升高ＰＡ活性为主，其活性能够被抑肽酶完全阻断。结论 肾脏局部毛细血管内沉积的纤维蛋白可能通过对ＣＦＣ ＰＡ／ＰＡＩ系统的调节发挥其病理作用。

Objective To investigate the effects of covering fibrin on the expression of plasminogen activators/plasminogen activators inhibitor in glomerular endothelial cells(GEC) . Methods RT-PCR. zymography. reverse zvmography and fibrin plate assay were used to detect the changes of tissue type plasminogen activator(tPA). urakinase type plasminogen activator(uPA) and their inhibitors(PAl-1) in GEC at levels of mRNA and protein activaties. Results After coculture with fibrin. mRNA expression of tPA. uPA and PAl-1 in GEC elevated significantly. PAI-l activities but not PA activities were detected in serum-free RPMI 1640 group. Fibrin treatment induced a dramatic expression of activities of tPA. uPA and PAI-1 in CEC in a dose and time dependent manner. Fibrinogen had similar effects with fibrin at the same concentration. Both cycloheximide and actinomycin D prevented the up-regulation of PA and PAI-1 expression induced by fibrin. Fibrin plate assay showed net effect of fibrin on the expression of PA/PAI activities was PA increment predominantly, which could be blocked completely by aprotinin. Conclusion Fibrin deposition may play an important role in regulating the PA/PAT system in GEC.