[Regulation of Reactive Oxygen Species on Platelet Activation and Apoptosis]

Objective: To investigate how reactive oxygen species (ROS) regulates the signal transduction of platelet activation and apoptosis, and to explore the relationship between platelet activation and apoptosis.

Methods: Platelets were directly stimulated with thrombin or pretreated with ROS inhibitor N-acetylcysteine (NAC) before being stimulated with thrombin, and then flow cytometry was used to detect the effects of thrombin and NAC on P-selectin expression, αⅡbβ3 activation, mitochondrial membrane potential depolarization, phosphatidylserine (PS) externalization, ROS expression and platelet aggregation.

Results: Thrombin could induce the production of ROS in platelets in a concentration- and time-dependent manner. 0.01 U thrombin induced ROS-dependent high degree of integrin αⅡbβ3 activation, P-selectin expression, and platelet aggregation. The platelets induced by different concentration gradients of thrombin exhibited ROS-dependent mitochondrial membrane potential depolarization and PS externalization in platelets. After induction with thrombin for 30 min, the activation of integrin αⅡbβ3 in platelets reached its maximum level, and after 60 minutes, the depolarization of mitochondrial membrane potential in platelets reached its maximum level. However, the expression of P-selectin, depolarization of mitochondrial membrane potential, and platelet aggregation function were all inhibited to a certain extent when the platelets were pretreated with ROS inhibitor NAC and then induced with thrombin.

Conclusion: When platelets are induced by thrombin, ROS first regulates the activation of platelets, and then regulates the apoptosis of platelets. Both platelet activation and apoptosis depend on the production of ROS in platelets, and the signals of activation and apoptosis occur orderly. Inhibiting the ROS signal in platelets can effectively inhibit the activation and apoptosis of platelets.