胞内钙与蛋白激酶C对人脐静脉内皮细胞组织因子途径抑制物及组织因子表达的影响

ROLES OF INTERCELLAR Ca^(2+) AND PROTEIN KINASE C PLAYED IN TISSUE FACTOR PATHWAY INHIBITOR AND TISSUE FACTOR EXPRESSION IN HUMAN UMBILIC VEIN ENDOTHELIAL CELLS

为探讨细胞内钙及蛋白激酶C在血管内皮细胞释放组织因子（TF），组织因子途径抑制物（TFPI）中的作用，本文采用钙离子载入剂A23187与蛋白激酶C激动剂佛波脂（PMA）刺激原代培养人脐静脉内皮细胞（HUVEC），观察各实验组内皮细胞冻融液中TF活性及条件培养液中TFPI活性的变化，以一期凝固法测TF活性，二期生色法测定TFPI活性。结果显示：A23187，PMA及A23187＋PMA组TF活性较对照明显升高（P＜0.001），三组中A23187和A23187＋PMA组活性明显低于PMA组（P＜0．05），但前两组间无显著性差异（P＞0．05）；A23187组TFPI活性与对照无明显差别，但PMA与A23187＋PMA组TFPI活性较对照及A23187组明显升高（P＜0.01）。结果提示：细胞内钙升高及PKC激活促进血管内皮细胞TF的合成，以PKC为强；PKC促进血管内皮细胞释放TFPI，而钙对此无明显作用。

The purpose of the present study was to elucidate the roles that protein kinase C (PKC) and calcium played in the tissue factor (TF) synthesis and tissue factor pathway inhibitory (TFPI) release in human umbilic vein endothelial cells (HUVEC). A23187 was used to represent calcium ionophore and phorbol 12-myristate 13-acetate (PMA) as that of PKC activator. TF activity in the lysed HUVEC was measured using one stage clotting assay. TFPI activity in the conditioned medium of HUVEC was assessed by the two-step chrom0ogenic method. The results showed that the TF activities in A23187, PMA and A23187 + PMA groups were remarkably higher (P < 0. 01 ) than that in control. Among the three treated groups, the TF activities in both A23187 group and A23187 + PMA group were lower than that in the PMA group (P < 0.05), but the difference between the former two groups was statically insignificant (P > 0.05). In contrast to the control group, the TFPI activity in the A23,87 group was not statistically different (P > 0.05) - However, the TFPI activities in the PMA group and the A23187 + PMA group were markedly higher than those in the control group and the A23,87 gr0up (P < 0.01 ). These findings indicate that PKC and calcium ion promote TF synthesis in HUVEC but the effect of the former is stronger than that of the latter, and that the release of TFPI from HUVEC is facilitated by PKC and not significantly affected by calcium ion.