[Effects of extracellular matrix on biological characteristics of late endothelial progenitor cells]

The present study was designed to investigate the effects of various extracellular matrix (ECM) proteins on the biological characteristics of late endothelial progenitor cells (EPCs). Density gradient centrifugation-isolated rat bone marrow mononuclear cells were cultured in complete M199 medium, which contained 15% fetal calf serum, 10 μg/L vascular endothelial growth factor (VEGF) and 5 μg/L basic fibroblast growth factor (bFGF). EPCs were plated on substrates containing fibronectin (Fn), laminin (Ln) or rat tail tendon collagen (Col), and the corresponding cells were defined as Fn, Ln and Col groups. The 3rd generation EPCs, namely late EPCs, were harvested. The proliferation, adhesion, migration and the ability of forming tubes were assayed using CCK-8, adhesion test, wound healing assay and Matrigel, respectively. The mRNA expressions of endothelial cell differentiation markers, vWF and CD31, were analyzed by real time RT-PCR. The apoptosis was assayed by flow cytometry (FCM). The results showed that cell proliferation ability of Fn and Col groups were higher than that of Ln group; Fn group showed increased adhesion compared to Col and Ln groups (P < 0.01); The migration ability of Fn and Col groups were higher than that of Ln group. Moreover, Fn group showed increased tube formation abilities compared to Col and Ln groups (P < 0.05). Although 24-hour free-serum-induced apoptosis in Ln group was the highest, there was no difference of auto-apoptosis among the three groups. Furthermore, the mRNA expressions of vWF and CD31 exhibited no difference among the three groups. These results suggest the ECM affects the biological functions of late EPCs, which would have a high probability of providing new directions that lead to the development of artificial heart and blood vessels.