Prostaglandin I₂ Inhibit Platelet Activation and Preserve Ultrastructure during Platelet Isolation by Centrifugation

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 a- 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 citrate- anticoagulated blood samples from healthy donors (n = 3), then being centrifuged at 150xg for 10 min. Platelets were then isolated from PRP with or without prostaglandin I2 (PGI(2), 2.5 - 10 mu g/mL) by centrifugation at 25degree celsius, either at low -speed (400xg for 20 min) or highspeed (14,000xg 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 low- speed (51 +/- 23% ) and highspeed (66 +/- 21%). At high-speed centrifugation, PRP treated with PGI2 at 10 mu g/mL was 1.5- to 5 -fold reduced in platelet activation compared to untreated PRP. However, PGI(2) had no effect in preventing platelet activation by low -speed centrifugation. Ultrastructure analysis of platelets is isolated by highspeed centrifugation with 10 mu g/mL PGI(2) present with preserved platelet ultrastructure contain alpha-granules, dense granules, mitochondria and open canalicular system. Conclusion: Therefore, 10 mu g/mL PGI(2) was suitable for inhibiting platelet activation during highspeed centrifugation.