Competence effect of basic fibroblast growth factor on cell cycle in subcultured endothelial cells of rat aorta by flow cytometry.

With flow cytometry, we investigated the effect of basic fibroblast growth factor (bFGF)-induced competence in subcultured endothelial cells (EC) (4-9-passage) of rat thoracic aorta. The cell population in each phase of the cell cycle was determined by a double staining technique with fluorescein isothiocyanate-conjugated mouse monoclonal antibody against the proliferation-associated nucleus antigen Ki-67 and propidium iodide for total DNA content. EC were cultured in medium containing 5% fetal bovine serum (FBS) for 6 days. After serum-starvation for 2 days, the treatment with bFGF (3-10 ng/ml) for 12 hr promoted the entry of cells into the G1 phase from the G0 phase concentration-dependently. bFGF (10 ng/ml) increased the cell population in the G1 phase by 5% of the total EC, compared with the control culture without bFGF. A further 12-15-hr culture with 1% FBS after bFGF treatment promoted the entry of the cell into the S phase. Thus flow cytometric analysis demonstrates that bFGF stimulates the entry of EC into the G1 phase from the G0 phase.