| Background: Platelets are shed from mature megakaryocytes,and the diameter of platelet is only 2-3?m.Platelets have stable quantity and structure in circulation,and play crucial role in hemostasis and thrombosis formation.In recent years,researchers had found that there are platelet apoptosis in vivo or in vitro.Platelet apoptosis plays an important role in platelet-related diseases.Anti-platelet treatment is necessary in clinical use.The platelet integrin ??b?3antagonists prevent ??b?3receptor on the surface of platelets from binding to fibrinogen,then incur thrombosis is difficult to form,so platelet integrin ??b?3antagonists have good effect on clinical antiplatelet therapy.How the ??b?3antagonists affect platelet apoptosis remains to be explored.Objective: The aim of this current study was to explore whether the platelet integrin??b?3antagonist affect platelet apoptosis induced by thrombin,when platelet integrin??b?3antagonist pre-incubated platelets in vitro.We further investigated the possible regulatory effect of ??b?3antagonist on platelet apoptosis process.Materials and methods: Venous blood were collected from healthy examiners aged18 to 30 years old?male 8,female 7,a total of 15 people?,after centrifugation and washed,human washed platelets were prepared.Washed platelets?3 × 108/ml?were incubated with related drugs,obtained five groups as follow:?1?negative control group;?2?positive control group;?3?tirofiban 0.05?g / ml group;?4?tirofiban 0.25?g /ml group;?5?tirofiban 0.5?g / ml group.After incubated with agonists,and related-antibody,flow cytometry was employed to measure the platelet apoptotic markers mitochondrial transmembrane potential???m?depolarization,phosphatidylserine?PS?exposure,and the generation of reactive oxygen species?ROS?,which promotes the process of platelet apoptosis.Results: 1.Thrombin induced ??m decreased,represented ??m depolarization,and PS exposure in platelets of positive control group,compared with platelets of negative control group?P?0.01?.This confirmed that thrombin induces platelet apoptosis.2.??m were all obviously higher in three different concentrations of tirofiban groups than positive group?P?0.01?,it shown that tirofiban obviously inhibited thrombin induced platelet apoptotic marker ??m depolarization,platelets apoptosis was reduced.And PS exposure were all decreased in three tirofiban groups?P?0.01?than positive group,differences between tirofiban groups and positive group had statistical significance.We found that comparisons between three concentrations of tirofiban groups,the effect on thrombin induced ??m depolarization and PS exposure had no statistical significance.3.The generation of ROS which promotes platelet apoptosis was higher in positive group compared with negative group?P?0.01?,it demonstrated that thrombin accelerated platelet apoptosis progress.4.The generation of ROS were all reduced in three different concentrations of tirofiban groups than positive group?P?0.01?,it shown that tirofiban inhibits platelet apoptosis progress.Comparisons between three concentrations of tirofiban groups,the effect on thrombin induced the generation of ROS had no statistical significance.Conclusions: Thrombin induced platelet apoptosis in vitro,??b?3antagonist pretreatment platelets inhibited platelet apoptotic markers ??m depolarization and PS exposure induced by thrombin,decreased the generation of ROS which promote platelet apoptosis,it reveals that ??b?3antagonist inhibits platelet apoptosis induced by thrombin.It suggests ??b?3antagonist has regulatory effect on platelet apoptosis induced by thrombin,and maybe through regulating ??m depolarization,PS exposure and the generation of ROS.This provides a new insight into the mechanism of platelet apoptosis,and provides a new reference for clinical antiplatelet apoptosis. |
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