Prostaglandin I<inf>2</inf> Inhibit Platelet Activation and Preserve Ultrastructure during Platelet Isolation by Centrifugation

Abstract

Background: Platelets play role in hemostasis, therefore, either decreasing or increasing in platelet structure/function affects hemodynamic disorders. Platelet structural abnormalities and platelet dysfunction can cause bleeding disorder. In contrast, an increasing in α-granules and mitochondria, increased circulating reticulated platelets and platelet hyperfunction which led to hypercoagulable state that contribute to thrombosis. Therefore, ultrastructural and platelet function analysis are required for diagnosis, determining molecular abnormalities, and exploring novel therapeutic approaches. Method: Platelet rich plasma (PRP) was collected from citrateanticoagulated blood samples from healthy donors (n = 3), then being centrifuged at 150×g for 10 min. Platelets were then isolated from PRP with or without prostaglandin I2 (PGI2, 2.5 - 10 μg/mL) by centrifugation at 25°C, either at low-speed (400×g for 20 min) or high-speed (14, 000×g for 2 min). Flow cytometric analysis was used to determine platelet activation (CD41a+CD62P+). Transmission electron microscope was used to determine ultrastructure of platelets. Results: Platelet activation was not significantly difference between whole blood (3±1%) and PRP (5±2%). Notably, centrifugation of PRP increased platelet activation at both lowspeed (51±23%) and highspeed (66±21%). At high-speed centrifugation, PRP treated with PGI2 at 10 μg/mL was 1.5- to 5-fold reduced in platelet activation compared to untreated PRP. However, PGI2 had no effect in preventing platelet activation by low-speed centrifugation. Ultrastructure analysis of platelets is isolated by highspeed centrifugation with 10 μg/mL PGI2 present with preserved platelet ultrastructure contain α-granules, dense granules, mitochondria and open canalicular system. Conclusion: Therefore, 10 μg/mL PGI2 was suitable for inhibiting platelet activation during highspeed centrifugation.