中文摘要：

目的探讨补体C5a对人脐静脉内皮细胞（HUVECs）血栓调节蛋白（TM）表达的影响。方法体外培养HUVECs，以终浓度200μg／L重组人C5a刺激HUVECs8、12、16、20h以及以终浓度100、200、300μg／L的C5a刺激HUVECs 12h，采用实时荧光定量聚合酶链反应（PCR）、蛋白质免疫印迹法（Western blotting）分别检测TM的mRNA及蛋白表达变化；观察C5a对其表达TM的时－效和量－效关系。结果C5a抑制了HUVECs在TM的mRNA和细胞膜表面蛋白水平表达。同时，C5a对TM表达的抑制作用存在时一效关系[8、12、16、20h时蛋白为（93．11±1．57）×10^-2、（71．05±3．39）×10^-2、（65．48±4．28）×10^-2、（62．69±4．03）×10^-2，mRNA为（301．71±80．40）×10^-6（38．29±20．24）×10^-6、（8．82±2．66）×10^-6、（7．05±0．80）×10^-6]，且均于12h后降低程度明显减缓（P均〈0．05）；并存在量-效关系（C5a100、200、300mg／L时蛋白为（113．25±3．97）×10、（80．18±2．56）×10、（73．22±4．36）X10，mRNA为（401．77±20．46）×10、（31．12±3．51）×10^-6、（18．19±1．46）×10^-6]，TM蛋白在C5a300μg／L、mRNA在C5a200μg／L时刺激12h降低程度明显减缓（P均〈0．05）。结论C5a通过抑制TM的结构基因表达，进而减弱TM的蛋白翻译，从而参与了脓毒症时凝血亢进、炎症损害的病理生理过程。

英文摘要：

Objective To investigate the effect of C5a on the expression of thrombomodulin （TM） in human umbilical vein endothelial cells （HUVECs）. Methods HUVECs cultured in vitro were stimulated with C5a for 8, 12, 16, 20 hours in a concentration of 200 μg/L, and also with different concentrations of 100, 200, 300 μg/L for 12 hours respectively. The levels of both mRNA and protein expression of TM was detected by real-time polymerase chain reaction （PCR） and Western blotting respectively, and the dose and time dependent effects of C5a on the expression of TM were evaluated. Results C5a down-regulated the TM expression at both protein and mRNA level. The down-regulation was time-dependent [（93.11 ± 1.57）×10^-2, （71.05±3.39）×10^-2, （65.48±4.28）×10^-2, （62.69±4.03）×10^-2at protein level and （301.71±80. 40）×10^-6, （38.29±20.24）×10^-6, （8. 82±2.66）×10^-6, （7.05±0.80）×10^-6at mRNA level, all P〈0. 05] and dose-dependent [（113.25 ± 3.97） ×10^-2, （80. 18 ± 2.56） × 10^-2, （73.22 ± 4. 36）×10^-2 at protein level and （401.77±20.46）×10^-6, （31.12±3.51）×10^-6, （18.12±3. 46）×10^-6 at mRNA level, all P〈0. 05]. When concentration of CSa at 300 μg/L was used to stimulate HUVECs for longer than 12 hours, the lowering of TM at protein level was slowed down obviously. And concentration of CSa at 200 μg/L was used to stimulate HUVECs for 12 hours, the lowering of TM at mRNA level was slowed down obviously. Conclusion C5a can depress the gene expression of TM, and then affect the proteinrs translation. By this means, C5a can lead to hypercoagulabillty and inflammatory injuries in sepsis.