Objective To investigate the effect of platelet-derived microparticles(PMP) on proliferation of human umbilical vein endothelial cells(HUVEC) and angiogenesis in chick chorioallantoic membranes (CAM). Methods The platelet concentrates were activated by 1 U/ml thrombin for 10 minutes and centrifuged at 800 g for 20 minutes,and supernatants enriched in PMP were collected by centrifugation at 17 000 g for 1 h.The protein concentration was measured using BCA method. HUVEC were incubated for 24 h with or without (control) PMP or VEGF,the effect of PMP on cell proliferation was analyzed by MTT assay. PMP were put into 9 day chick embryo. Chicken CAMs angiogenesis were observed at 72 h after incubation.Result PMP stimulated HUVEC proliferation.After 24 h of incubation,PMP stimulated HUVEC proliferation in a dose-dependent manner. At the concentration of 40 μg/ml PMP,the proliferation rate of HUVEC was as 1.83±0.33 times as control and there was no difference with the group of vascular endothelial growth factor (VEGF),which the proliferation rate was 1.91±0.47 times vs. control (P0.05).Better effects were obtained in the formation of capillary and the count of blood vessel in groups treated by PMP,compared with the NS control group(P0.05) and compared with the VEGF(P0.05).Conclusion PMP could stimulate proliferation of HUVEC,and induce the formation of new blood vessels.