急性肺损伤患者血清C5a对肺血管内皮细胞依赖性粘附的影响

目的 探讨急性肺损伤(ALI)早期肺血管内皮细胞损伤的机制及介导血管内皮细胞依赖性粘附的分子基础。方法 夹心酶联免疫吸附(ELISA)法测定和比较正常人及ALI后患者血清中C5a的含量；用流式细胞术(FCM)检测ALI患者血清刺激人肺血管内皮细胞，观测其表面粘附分子：P选择素和细胞间粘附分子(ICAM)—1的表达变化，同时通过检测粘附子血管内皮细胞表面的中性粒细胞(PMN)中髓过氧化物酶(MPO)活性，间接反映血管内皮细胞表面PMN的粘附和聚集。结果 ALI患者血清中C5a含量明显升高，同正常组比较差异有显著性；原代培养的肺血管内皮细胞，受ALI患者血清刺激后，其表面P—选择素的表达迅速增加，20min达到高峰，60min后开始降低，而ICAM—l的表达较慢，3h开始升高，12h达到最高值，24h内无明显下降，仍维持在较高水平；血管内皮细胞表面粘附的PMN中MPO的活性，3h明显升高，12h后达到最高值。结论 ALI患者血清中C5a含量明显升高，促进了PMN在肺微血管内的扣押、聚集进而同血管内皮细胞相粘附；而血管内皮细胞依赖性粘附的增强，主要是源血管内皮细胞上P—选择素和ICAM—l的表达增加，它们在ALI的发生、发展中起到重要作用。

Effects of serum complement C5a on PVEC based adhesion in patients with acute lung injury

Objective To study the mechanism of pulmonary vascular endothelial cell (PVEC) injury early after acute lung injury (API) and the molecular base of vascular endothelial cell (VEC) based adhesion.Methods The serum concentration of C5a (des arg) was determined by specific ELISA.The changes of adhesion molecule expression in PVEC were detected by flowcytometry and the activity of MPO in PMN was determined after adhesion.Results The serum concentration of C5a (des Arg) was increased after ALI.In response to serum of ALI patients,the expression of P Selectin in PVEC was increased significantly and reached the peak at 20 min,decreased after 60 min.But the expression of ICAM-1 was increased gradually and reached the peak at 12 h.In addition,the activity of MPO in PMN was also increased after 3 h and reached the peak at 12 h.Conclusion The serum concentration of C5a was increased significantly after ALI,so to accelerate the recruitment of PMN in pulmonary vessels and adhesion to PVEC.At the same time,the enhancement of VEC-based adhesion is mostly derived from the upregulation of P-Selectin and ICAM-1 expressions in PVEC.They all played a great role in the development of ALI.