Pastakia K B, Terle D, Prodouz K N
Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Bethesda, MD 20892.
J Lab Clin Med. 1993 Apr;121(4):546-54.
We examined the effects of the beta-lactam antibiotic penicillin G on platelet function and on specific membrane glycoproteins in vitro. Platelet concentrates exposed to 3 to 10 mmol/L penicillin for 48 hours showed irreversible inhibition of aggregation by thrombin in washed platelets after removal of the antibiotic. Although a brief 15-minute exposure to similar doses of penicillin also inhibited thrombin aggregation, the inhibition was reversed on removal of the penicillin by washing. Aggregation activity was also restored to normal levels by stimulation with high thrombin concentrations (> 0.4 U/ml). Results of the aggregation studies led us to examine how penicillin affects platelet membrane proteins. Membranes isolated after 48 hours of exposure of platelet concentrates to penicillin showed no differences from the control in total protein profiles on sodium dodecylsulfate--polyacrylamide gel electrophoresis or in the glycoprotein Ib or IIb content on immunoblotting. However, flow cytometric analysis with fluorescently labeled monoclonal antibodies revealed that exposure of platelets to penicillin for 15 minutes inhibited thrombin-induced modulations in the glycoproteins Ib, Ib-IX, IIb-IIIa, and P-selectin. These effects were observed with washed platelets and platelets in plasma. Penicillin also inhibited the regulation of expression of glycoproteins Ib-IX and IIb-IIIa in adenosine diphosphate--activated platelets. The inhibitory effects were partially reversed at high agonist concentrations.
我们在体外研究了β-内酰胺抗生素青霉素G对血小板功能及特定膜糖蛋白的影响。血小板浓缩物在3至10 mmol/L青霉素中暴露48小时后，去除抗生素后，洗涤过的血小板中凝血酶诱导的聚集呈现不可逆抑制。尽管短暂暴露于类似剂量的青霉素15分钟也会抑制凝血酶聚集，但通过洗涤去除青霉素后，抑制作用会逆转。通过高浓度凝血酶（> 0.4 U/ml）刺激，聚集活性也可恢复至正常水平。聚集研究结果促使我们研究青霉素如何影响血小板膜蛋白。血小板浓缩物暴露于青霉素48小时后分离得到的膜，在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上的总蛋白图谱，或免疫印迹上的糖蛋白Ib或IIb含量，与对照均无差异。然而，用荧光标记单克隆抗体进行的流式细胞术分析显示，血小板暴露于青霉素15分钟会抑制凝血酶诱导的糖蛋白Ib、Ib-IX、IIb-IIIa和P-选择素的调节。在洗涤过的血小板和血浆中的血小板中均观察到了这些效应。青霉素还抑制二磷酸腺苷激活的血小板中糖蛋白Ib-IX和IIb-IIIa表达的调节。在高激动剂浓度下，抑制作用会部分逆转。
