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目的探讨同型半胱氨酸(homocysteine,Hcy)对血管内皮细胞纤溶系统影响。方法(1)将体外培养的人脐静脉血管内皮细胞(HUVEC)分为10个实验组(0、10、50、200、500μmol/LHcy组及叶酸和上述各Hcy点共同培养组),培养24h后,酶联免疫吸附实验法(ELISA)测定各组细胞上清液中纤溶酶原激活剂(plasminogenactivator,tPA)及纤溶酶原激活物抑制剂1(plasminogenactivatorinhibitor1,PAI1)抗原含量,逆转录聚合酶链反应分析(RTPCR)法分析各组tPA及PAI1的mRNA表达水平。(2)急性心肌梗死(AMI)患者53例及健康对照组48例,ELISA测定空腹血浆tPA及PAI1含量,高效液相色谱法测定血浆Hcy水平。结果(1)500μmol/LHcy组PAI1抗原及mRNA表达水平均明显增高(P<0.05)。(2)以单纯培养基为对照组,生理浓度Hcy组内皮细胞tPA抗原合成及mRNA表达明显增高(P<0.05),而以10μmol/LHcy组为对照组时,500μmol/LHcy组tPA抗原合成及mRNA表达水平则明显减少(P<0.05)。(3)500μmol/LHcy与叶酸共同培养组和单纯Hcy组相比,可以明显提高内皮细胞tPA抗原的合成及mRNA表达,减少PAI1抗原合成及mRNA表达(P<0.05)。(4)AMI组Hcy、tPA及PAI1均明显高于健康对照组(P<0.05)。结论在体外细胞时,超生理浓度Hcy可以通过下调tPA、上调PAI1的mRNA表达,减少内皮细胞tPA抗原的分泌及增加PAI1抗原的合成,可能降低纤溶系统的活性。叶酸则可以减少Hcy引起内皮细胞纤溶系统的损害,起到保护作用。Hcy是AMI的一个独立危险因素。
Objective To investigate the effect of homocysteine (Hcy) on fibrinolytic system of vascular endothelial cells. Methods (1) Human umbilical vein endothelial cells (HUVEC) cultured in vitro were divided into 10 experimental groups (0, 10, 50, 200 and 500 μmol / LHcy groups and folic acid and the above Hcy co-culture group) The levels of antigens of plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI1) in the cell supernatants were determined by enzyme-linked immunosorbent assay (ELISA) The mRNA expression levels of tPA and PAI1 in each group were analyzed by polymerase chain reaction (RTPCR). (2) 53 cases of acute myocardial infarction (AMI) and 48 cases of healthy control group. The contents of tPA and PAI1 in fasting plasma were measured by ELISA, and plasma Hcy level was measured by high performance liquid chromatography. Results (1) PAI1 antigen and mRNA expression in 500μmol / LHcy group were significantly increased (P <0.05). (2) Compared with the control group, the tPA antigen synthesis and mRNA expression in the endothelial cells in the physiological concentration Hcy group were significantly increased (P <0.05). However, the tPA antigen synthesis in the 500μmol / LHcy group mRNA expression was significantly reduced (P <0.05). (3) 500μmol / LHcy could significantly increase the synthesis and mRNA expression of tPA antigen and decrease the PAI1 antigen synthesis and mRNA expression (P <0.05) compared with folic acid co-culture group and Hcy group alone. (4) The levels of Hcy, tPA and PAI1 in AMI group were significantly higher than those in healthy control group (P <0.05). Conclusions Hcy can reduce the activity of fibrinolytic system by down-regulating tPA, up-regulating the mRNA expression of PAI1, decreasing the secretion of tPA antigen in endothelial cells and increasing the synthesis of PAI1 antigen in vitro in vitro. Folic acid can reduce Hcy-induced endothelial fibrinolysis damage, play a protective role. Hcy is an independent risk factor for AMI.