Winocour P D, Kinlough-Rathbone R L, Richardson M, Mustard J F
J Clin Invest. 1983 Jan;71(1):159-64. doi: 10.1172/jci110745.
Platelet survival in rabbits and rats is shortened by placing indwelling catheters in the aorta; this shortening appears to be at least partly related to the extent of vessel wall injury and platelet interaction with the repeatedly damaged wall. Treatment of rabbit platelets with plasmin and other proteolytic enzymes in vitro shortens their survival when they are returned to the circulation. Because platelets may be exposed to plasmin and other proteolytic enzymes in rabbits and rats with indwelling aortic catheters, we examined the effect of epsilon-aminocaproic acid (EACA) on platelet survival in rats. At a dose of 1 g/kg every 4 h, EACA significantly reduced whole blood fibrinolytic activity and prolonged the shortened platelet survival in rats with indwelling aortic catheters. Mean platelet survival for untreated rats with indwelling aortic catheters was 38.6 +/- 1.9 h, and for rats treated with EACA, 53.8 +/- 3.8 h. Scanning electron microscopy showed that the injured vessel wall of these animals was mainly covered with platelets and fibrin, whereas in control animals that did not receive EACA, the injured surface was mainly covered with platelets and little fibrin was observed. Thus shortened platelet survival during continuous vessel wall injury may result from the local generation of plasmin or the release of proteolytic enzymes at sites where platelets (and possibly leukocytes) interact with the vessel wall.
通过在兔和大鼠的主动脉中留置导管，可缩短其血小板存活时间；这种缩短似乎至少部分与血管壁损伤程度以及血小板与反复受损壁的相互作用有关。体外使用纤溶酶和其他蛋白水解酶处理兔血小板后，再将其回输到循环系统中，会缩短它们的存活时间。由于在留置主动脉导管的兔和大鼠中，血小板可能会接触到纤溶酶和其他蛋白水解酶，我们研究了ε-氨基己酸（EACA）对大鼠血小板存活的影响。以每4小时1 g/kg的剂量给药，EACA可显著降低全血纤溶活性，并延长留置主动脉导管大鼠缩短的血小板存活时间。未治疗的留置主动脉导管大鼠的平均血小板存活时间为38.6±1.9小时，而接受EACA治疗的大鼠为53.8±3.8小时。扫描电子显微镜显示，这些动物受损的血管壁主要覆盖有血小板和纤维蛋白，而在未接受EACA的对照动物中，受损表面主要覆盖有血小板，几乎观察不到纤维蛋白。因此，在持续的血管壁损伤过程中血小板存活时间缩短，可能是由于纤溶酶的局部生成或在血小板（可能还有白细胞）与血管壁相互作用的部位蛋白水解酶的释放所致。
