Platelet-Derived Microparticles Induce Angiogenesis In Vitro and In Vivo.

Objective: An attempt was made to investigate the effect of platelet-derived microparticles (PMPs) on the angiogenesis.

Methods: Thrombin was adopted to activate the platelets to release PMPs. Flow cytometry(FCM)was adopted to evaluate the efficiencies of different concentrations of thrombin to produce PMPs and BCA was adopted to evaluate the content of PMPs. By the carrier of human umbilical vein cell line ECV-304 cultivated in vitro, investigate the effect of PMPs on the proliferation and apoptosis of human umbilical vein endothelial cells using MTT and FCM. PMPs were put into CAM and observe the effects of PMPs on angiogenesis in Chick embryo chorioallantoic membrane (CAM).

Results: The efficiencies of PMPs activated by 1.0U/ml thrombin were 50.1%; PMPs induced proliferation of human umbilical vein cell line ECV-304 in a dose dependent manner. At the concentration of 40ug/ml PMPs, the proliferation rate of human umbilical vein cell line ECV-304 was as 1.8±0.3 times as control and there was no difference with the group of vascular endothelial growth factor (VEGF),which the proliferation rate was 1.9±0.5 times vs. control, p > 0.05;PMPs inhibited human umbilical vein cell line ECV-304 apoptosis. Compared with control group (apoptosis rate 9.4%±0.5%), apoptosis rate of PMPs (40μg/ml) is 3.9%±0.4%, which was significantly reduced, p<0.05. The addition of VEGF (10μl/ml) did not successfully prevented apoptosis of human umbilical vein cell line ECV-304 (apoptosis rate 8.0%±0.8%);After 72 h of incubation, showing an implant of PMPs by allantoic vessels developing radially towards it (implant) in a ’spoked-wheel’ pattern, at the concentration of 80μg/ml PMPs, number of vessel ramification is 112.5±11.31 and vessel area/CAM area is (6.19±1.29)%, compared with the VEGF(p>0.05). But there are not localized allantoic vessels developing in the NS control group(P<0.05).

Conclusion: 1.0U/ml thrombin activated platelet could get the best efficiency of PMPs, which could stimulate proliferation of human umbilical vein cell line ECV-304 and inhibit its apoptosis and PMPs have certain promotive effect on the formation of capillary in chick chorioallantoic membranes.