[Effects of platelet-derived membrane microparticles on the proliferation and apoptosis of human umbilical vein endothelial cells].

This study was purposed to investigate the effects of platelet-derived membrane microparticles (PMP) on the proliferation and apoptosis of human umbilical vein endothelial cells (HUVEC). Different concentrations of thrombin were adopted to activate the platelets so as to release PMPs. Flow cytometry (FCM) was adopted to evaluate the efficiencies of different concentrations of thrombin to release PMPs. By using the HUVEC cultivated in vitro as vector, the effects of PMPs on the proliferation and apoptosis of HUVEC were investigated by MTT and FCM. The results showed that the efficiencies releasing PMPs from platelets activated by 2.0, 1.5, 1.0, 0.5 U/ml thrombin were 28.7, 47.7, 50.1 and 43.9% respectively; PMPs induced proliferation of HUVEC in a dose dependent manner. At the concentration of 40 microg/ml PMPs, the proliferation rate of HUVEC was 1.8 +/- 0.3 times as much as blank control, the proliferation rate in group of vascular endothelial growth factor was 1.9 +/- 0.5 times of as much as blank control, there was no statistic difference (p > 0.05). The PMPs inhibited HUVEC apoptosis. Compared with the apoptosis rate of control (9.4 +/- 0.5)%, apoptosis rate in PMP group (40 microg/ml) was (3.9 +/- 0.4)% (p < 0.05). The addition of VEGF (10 microl/ml) did not successfully prevented apoptosis of HUVEC with apoptosis rate of (8.0 +/- 0.8)%. It is concluded that platelets activated by 1 U/ml thrombin gets the best efficiency of PMP release, which stimulates proliferation of HUVEC and inhibits its apoptosis.