Mouthon Marc-André, Vereycken-Holler Valérie, Van der Meeren Anne, Gaugler Marie-Hélène
Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses Cedex, France.
Radiat Res. 2003 Nov;160(5):593-9. doi: 10.1667/3068.
Adhesion of platelets to the endothelium is believed to be a major factor contributing to thrombosis and vascular occlusion after radiotherapy or endovascular irradiation. In the present study, platelet-endothelium interactions were analyzed in vivo by intravital microscopy in mesenteric venules of mice according to three parameters: (1) platelet rolling, (2) platelet adhesion, and (3) the presence of platelet clusters. A 10-Gy total-body irradiation of mice resulted in an increase in the frequency of appearance of these three types of platelet-endothelium interactions in postcapillary venules 6 and 24 h after exposure, whereas only minor alterations were seen in large venules. In addition, the duration of platelet adhesion was increased 24 h after irradiation in both postcapillary and large venules. However, P-selectin was not up-regulated on the platelet membrane and platelet-leukocytes were not seen rolling together, suggesting that changes in platelet-endothelial cell interaction result from endothelial cell activation rather than platelet activation. Our data suggest that irradiation transforms resting endothelial cells to a pro-adhesive surface for platelets, which could ultimately lead to thrombosis.
血小板与内皮的黏附被认为是放疗或血管内照射后导致血栓形成和血管闭塞的主要因素。在本研究中，通过活体显微镜观察小鼠肠系膜小静脉，根据三个参数对体内血小板 - 内皮相互作用进行了分析：（1）血小板滚动，（2）血小板黏附，以及（3）血小板聚集体的存在。对小鼠进行10 Gy全身照射后，在照射后6小时和24小时，后微静脉中这三种类型的血小板 - 内皮相互作用的出现频率增加，而在大静脉中仅观察到轻微改变。此外，照射后24小时，后微静脉和大静脉中血小板黏附的持续时间均增加。然而，血小板膜上的P - 选择素未上调，且未观察到血小板与白细胞一起滚动，这表明血小板 - 内皮细胞相互作用的变化是由内皮细胞活化而非血小板活化引起的。我们的数据表明，照射将静止的内皮细胞转变为血小板的促黏附表面，这最终可能导致血栓形成。
