同型半胱氨酸对人脐静脉血管内皮细胞tPA及PAI-1基因表达的影响

HOMOCYSTEINE’S EFFECT ON tPA AND PAI-1 GENE EXPRESSION IN HUVEC

目的探讨同型半胱氨酸(Hcy)对纤溶系统的影响,观察Hcy在转录水平对人脐静脉血管内皮细胞(HUVEC)表达组织型纤溶酶原激活物(tPA)和纤溶酶原激活物抑制剂1(PAI1)的影响。方法将体外培养的HUVEC分为生理浓度(10μmol/LHcy)组,病理浓度(50、200、500μmol/L)Hcy组及单纯培养基组(0μmol/LHcy),培养24h后,提取RNA,反转录聚合酶链反应分析(RTPCR)法分析各组tPA及PAI1基因表达水平。结果500μmol/LHcy组与10μmol/LHcy组相比,tPAmRNA基因表达明显下调(P<0.05),PAI1mRNA表达则明显上调(P<0.05)。而与单纯培养基组相比,10μmol/LHcy组tPAmRNA表达明显增高(P<0.05)。结论生理浓度Hcy可以增加纤溶系统活性,减少血栓性疾病的发生。高Hcy(病理浓度)则抑制纤溶系统活性,促进缺血性心脑血管疾病的发生。

Aim: In order to elucidate the relationship between homocysteine (Hcy) and the fibrinolytic system, we examined the effect of Hcy on tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI 1) gene expression in human umbilical vein endothelial cells (HUVEC) in vitro . Methods: Total RNA was extracted from HUVEC exposed to physical and pathological concentrations of Hcy (0, 10, 50, 200, 500 μmol/L ) for 24 hours, using the guanidinium isothiocyanate method. The semi quantification of tPA and PAI 1 mRNA in HUVEC was carried out by reverse transcriptase polymerase chain reaction(RT PCR). Results: PAI 1 mRNA levels was enhanced by Hcy at concentrations of 500 μmol/L of Hcy, compared with that of 0μmol/L Hcy ( P <0.05). The mRNA expression of tPA,however, was significantly decreased at concentrations of 500 μmol/L Hcy , compared with that of 10μmol/L Hcy ( P <0.05), but compared with the control group, the tPA level of 10 μmol/L Hcy was much higher( P < 0.05). Conclusion:Hyperhomocysteinemia increases the incidence of cardio cerebral vascular disease, which may be caused by decreasing the activity of fibrinolytic system, whereas, the physiological concentration of Hcy may be decreased the incidence by enhancing the activity of fibrinolytic system.