[Differential time attachment: optimization of the adherent time to obtain mouse bone marrow-derived endothelial...

The different biological functions were studied in mouse bone marrow-derived endothelial progenitor cells isolated by differential time attachment to obtain the optimal adherent time in this study. Density gradient centrifugation-isolated bone marrow mononuclear cells were seeded on the fibronectin-coated dish. The 1-day cultured unattached cells were seeded on the second dish for 2 more days. Then unattached cells in the second dish were seeded on the third dish. The cells on 3 dishes were defined as 1-day adherent cells, 3-day adherent cells and 3-day unattached cells, respectively. After 20-day culture, the biological functions, such as the percentage of biomarkers, the ability of adhesion, and the ability of forming tubes in vitro were analyzed. The results showed that the percentages of positive CD34, FLK-1, and CD34/FLK-1 expressions in 1-day attached cells were significantly increased compared to those in the 3-day adherent or unattached cells (P < 0.01), which showed the strongest adhesion ability. The expression of eNOS in 1- or 3-day adherent cells was significantly higher than that in 3-day unattached cells (P < 0.01). The expression of VEGF in 3-day adherent cells was significantly higher than that in 1-day adherent cells or 3-day unattached cells (P < 0.01). These results suggest the biological functions of 1-day adherent cells are significantly stronger than that of 3-day adherent or unattached cells. VEGF expression in 3-day adherent cells is higher than that in 1-day adherent cells or 3-day unattached cells. The expression of eNOS in 1-day adherent cells or 3-day adherent cells is higher than that in 3-day unattached cells. The optimal adherent time to obtain mouse bone marrow-derived endothelial progenitor cells is 1-3 d.