脂蛋白的氧化修饰对血凝及纤溶活性的影响

目的:研究脂蛋白的氧化修饰对凝血及纤溶活性的影响。方法:用Cu²⁺法及次氯酸法氧化修饰超速离心分离的正常人血浆极低密度脂蛋白(VLDL)、低密度脂蛋白(LDL)及高密度脂蛋白(HDL)。分别将天然及氧化修饰脂蛋白N-VLDL、Ox-VLDL;N-LDL、Ox-LDL、N-HDL及Ox-HDL加入由正常人新鲜混合血浆构成的反应系统中,以相应天然脂蛋白为对照,测定凝血酶原时间(PT)、活化部分凝血酶原时间(APTT)、组织型纤溶酶原激活物(t-PA)活性、纤溶酶原激活物抑制剂1(PAI-1)活性及血小板最大聚集率。结果:VLDL、LDL及HDL经Cu²⁺法及次氯酸法氧化修饰后其REM、234nm吸光度值、TBARS含量均显著大于对照组(P<0.01)。Ox-VLDL、Ox-LDL及Ox-HDL使PT及APTT明显短于对照组(P<0.05或P<0.01),血小板聚集率明显高于对照组(P<0.01)。Ox-VLDL及Ox-LDL使t-PA活性高于对照组,PAI-1活性低于对照组(P<0.05及P<0.01),而Ox-HDL对t-PA活性及PAI-1活性的影响与对照组无明显差别。结论:N-VLDL、N-LDL及N-HDL对凝血及纤溶活性无影响。Ox-VLDL、Ox-LDL及Ox-HDL促进血凝及血栓形成;Ox-VLDL及Ox-LDL使纤溶活性增加,而Ox-HDL对纤溶活性无明显影响。

Effects of oxidative modification of lipoproteins on blood coagulation and fibrinolysis

AIM: To study the effects of oxidative modification lipoproteins on blood coagulation and fibrino (lysis) in vitro. METHODS: Normal human plasma VLDL, LDL and HDL, which were isolated by density gradient ultracentrifugation method, were oxidatively modified by Cu~(2 ) and HOCl method. N-VLDL, Ox-VLDL, N-LDL, Ox-LDL, N-HDL, Ox-HDL were added to the reaction system which consisted of mixed fresh normal plasma respectively, prothrombin time (PT), activated partial thrombplastin time (APTT), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA) and platelet aggregation were measured according to the direction of the kits. RESULTS: The relative electrophoretic mobility (REM), absorbance at 234nm and TBARS of oxidized VLDL, LDL and HDL mediated by HOCl or Cu~(2 ) were significantly higher than that of the control group (P<0.01). N-VLDL, (N-LDL) and N-HDL had no effect on PT, APTT, t-PA, PAI-1 and platelet aggregation. The PT and APTT of (Ox-VLDL,) Ox-LDL and Ox-HDL were significantly shorter than that of the control group (P<0.05 and (P<0.01)). The platelet aggregation of Ox-VLDL, Ox-LDL and Ox-HDL were significantly stronger than that of the control group (P<0.01). The Ox-VLDL and Ox-LDL were higher in t-PA and lower in PAI-1 than that of the control group (P<0.05 and (P<0.01)), but the Ox-HDL had no influences on t-PA and PAI-1 activity. CONCLUSIONS: N-VLDL, N-LDL and N-HDL have no effects on blood coagulation and fibrinolysis in vitro. Ox-VLDL, Ox-LDL and Ox-HDL enhance blood coagulation and thrombosis. Ox-VLDL and Ox-LDL enhance t-PA activity and decreased PAI-1 activity, but Ox-HDL does not affect the fibrinolysis activity.