Yang H L, Chiu H C, Lu F J
Department of Nutrition, China Medical College, National Taiwan University, Taipei, R.O.C.
Am J Hematol. 1996 Mar;51(3):200-6. doi: 10.1002/(SICI)1096-8652(199603)51:3<200::AID-AJH4>3.0.CO;2-0.
We have previously shown that humic acid (well-water humic acid, HA, and synthetic humic acid, SHA) enhances cell surface expression of tissue factor (TF). Here we report that incubation of human umbilical vein endothelial cells (HUVEC) for 2 hr with HA or SHA cause a rapid rise in TF mRNA levels, as shown by Northern blot analysis. To understand the cytotoxic and fibrinolytic effects of HA and SHA on cultured HUVEC, the cells treated with varying concentrations of HA and SHA for various periods of time. Both HA and SHA (10-200 micrograms/ml) inhibited the viability of subconfluent HUVEC, cultured in the presence or absence of 20% FBS (Fetal Bovine serum) in the culture medium, in a dose-dependent manner. Both HA and SHA induced surface changes in the HUVEC as revealed by scanning electron micrography (SEM). However, protocatechuic acid, the monomer of SHA, did not significantly inhibit cell growth, and showed a cytotoxic effect only at 200 micrograms/ml. Furthermore both HA and SHA stimulated HUVEC to produce plasminogen activator inhibitor (PAI-1) and tissue plasminogen activator (t-PA) in a dose and time dependent fashion; the amount of PAI-1 produced was found to exceed that of t-PA. The monomer of SHA did not have this stimulatory effect. These results distinctly suggest that in addition to the inhibition of viability HA is involved in TF induction and PAI-1 synthesis in HUVEC and these may be some of the plausible mechanisms underlying the thrombotic disorders in Blackfoot disease.
我们之前已经表明，腐殖酸（井水腐殖酸、HA以及合成腐殖酸、SHA）可增强组织因子（TF）的细胞表面表达。在此我们报告，用HA或SHA孵育人脐静脉内皮细胞（HUVEC）2小时会导致TF mRNA水平迅速升高，Northern印迹分析表明了这一点。为了解HA和SHA对培养的HUVEC的细胞毒性和纤溶作用，用不同浓度的HA和SHA处理细胞不同时间。HA和SHA（10 - 200微克/毫升）均以剂量依赖方式抑制亚汇合状态的HUVEC的活力，无论培养基中是否存在20%胎牛血清（FBS）。扫描电子显微镜（SEM）显示，HA和SHA均诱导了HUVEC的表面变化。然而，SHA的单体原儿茶酸并未显著抑制细胞生长，仅在200微克/毫升时显示出细胞毒性作用。此外，HA和SHA均以剂量和时间依赖方式刺激HUVEC产生纤溶酶原激活物抑制剂（PAI - 1）和组织纤溶酶原激活物（t - PA）；发现产生的PAI - 1量超过t - PA。SHA的单体没有这种刺激作用。这些结果清楚地表明，除了抑制活力外，HA还参与了HUVEC中TF的诱导和PAI - 1的合成，而这些可能是黑脚病血栓形成紊乱的一些潜在机制。
