Abstract:

BACKGROUND: Platelet-rich plasma is the plasma containing rich platelet extracted by special method. Compared with common serum, platelet-rich plasma contains richer cytokines, such as platelet derived growth factor, transforming growth factor beta and vascular endothelial growth factor.
OBJECTIVE: To observe effects of platelet-rich plasma on biological characteristics of human endothelial progenitor cells (EPCs), and to discuss the repair function of platelet-rich plasma on bone defects.
METHODS: Platelet-rich plasma was collected from autologous peripheral vein blood of 16 healthy volunteers. EPCs were harvested from bone marrow blood by density gradient centrifugation. EPCs following 8 days of culture were randomly assigned to control group, platelet-rich plasma group, fetal bovine serum group and serum-free control group. In the fetal bovine serum group, cells were incubated in high-glucose DMEM containing 10% fetal bovine serum, 100 U/mL penicillin and 100 U/mL streptomycin. In the serum-free control group, cells were incubated in high-glucose DMEM containing 100 U/mL penicillin and 100 U/mL streptomycin. EPC growth was observed under a phase contrast microscope and a laser confocal microscope. AC133- and vWF- positive cells (double staining) were differentiated EPCs. EPC proliferation, migration and tubule formation capacity were respectively measured by the MTT assay, Transwell chamber assay and Matrigel tubule assay at 6, 12, 48 hours following culture.
RESULTS AND CONCLUSION:  ① Cells from each group began to adhere to the wall, and changed from round to spindle, polygonal and irregular shapes at 12-24 hours following incubation. ② A490 value in EPCs was significantly greater following 6 hours of treatment with platelet-rich plasma compared with the control group (P < 0.05), and the promotion effect became stronger at 12 hours (P < 0.01). At 0-48 hours, with prolonged time, the promotion effect of platelet-rich plasma on EPC proliferation enhanced. ③ Platelet-rich plasma could elevate EPC migration, and the effect became significantly enhanced at 6 hours (P < 0.05), peaked at 12 hours (P < 0.01), decreased at 48 hours, and still significantly greater than the control group (P < 0.01). ④ Platelet-rich plasma obviously enhanced tubule formation capacity in EPCs in vitro, especially at 48 hours, and the tubule-like structure is more complicated compared with the control group.