The Study Of Xinmailong On Antiplatelet And Antithrombotic Effect

Part ? The effects of Xinmailong on human platelet function and its mechanism[Objectives]:Inappropriate activation of platelets under some pathological conditions leads to thrombosis,which result in acute coronary syndrome or stroke.We study the effects of Xinmailong on human platelet function and its mechanism.[Methods]:The effects of Xinmailong on different agonist(thrombin,collagen and arachidonic acid,AA)-induced platelet aggregation and induced ATP secretion were examined with an aggregometer.The effects of Xinmailong on different agonist(thrombin,collagen and AA)-induced P-selectin expression and induced PAC-1 expression were examined by flow cytometric.The effects of Xinmailong on platelet adhesioning to immobilized collagen and spreading on immobilized fibrinogen were observed with immunofluorescence.The effects of Xinmailong on clot retraction were also investigated.Western blot was used to detect the effects of Xinmailong on major protein of platelet signaling pathway of GPVI-Syk-PLCy2-MAPK and PI3K-Akt-GSK3?.[Results]:Xinmailong inhibited human PRP and washed platelet aggregation by thrombin,collagen and AA.Xinmailong also inhibited thrombin,collagen and AA induced granule secretion.The number of adherent platelets on immobilized collagen was markedly reduced by pretreatment with Xinmailong.Xinmailong also inhibited platelet spreading area on immobilized fibrinogen.Xinmailong attenuated the phosphorylation of GPVI-Syk-PLCy2-MAPK and PI3K-Akt-GSK3? in platelets stimulated by thrombin,collagen and AA.Xinmailong and PP2/LY294002 demonstrated an additive inhibition on aggregation when combined.Xinmailong also reduced clot retraction.[Conclusions]:This study demonstrates for the first time that Xinmailong possesses antiplatelet activity by inhibiting platelet aggregation,release,adhesion and spreading.The underlying mechanism is related to its inhibiting the GPVI-Syk-PLC?2-MAPK and PI3K-Akt-GSK3? pathway,namely platelet"inside-out" and "outside-in" signaling pathway.Part ? The effects of Xinmailong on antithrombotic in rats or mice[Objectives]:To further study the effect of Xinmailong on thrombosis and coagulation system in rats or mice.[Methods]:The effects of Xinmailong on different agonist(thrombin,collagen and arachidonic acid,AA)-induced platelet aggregation in rat in vivo were examined with an aggregometer.The effects of Xinmailong in ex vivo coagulation time and mouse tail bleeding time were also tested.The effects of Xinmailong on mice survival time and the corresponding pathological changes in lung tissue were investigated by collagen-epinephrine-induced acute pulmonary thrombus formation mouse model.[Results]:Xinmailong inhibited thrombin,collagen and AA induced platelet aggregation in vivo.Xinmailong had no effect on the coagulation time(PT?APTT)and mouse tail bleeding time.Xinmailong significantly attenuated thrombus formation and survival time by collagen-epinephrine-induced acute pulmonary thrombus mouse model.[Conclusions]:Xinmailong inhibits thrombosis in vivo by affecting the function of platelet.