Effect of H-RN on HUVEC cell cycle. Cells were incubated in serum-free medium with 100 ng/ml VEGF, 150 μM H-RN or 1.5 mM H-RN for 24 h. A-D: Cell cycle distribution analysis by flow cytometry. Ordinate represents cell number, abscissa represents DNA content. The first sharp peak represents G0/G1 phase cells, the following lower peak represents G2/M phase cells, and the area between them represents S phase cells. The numbers on the right part of each figure represent the percentage of cells in each phase. A: control group; B: 100 ng/ml VEGF group; C: 150 μM H-RN group; D: 1.5 mM H-RN group. E-G: Statistical analysis among different groups. E: Statistical analysis of the percentage of G0/G1 phase cells among different groups; F: Statistical analysis of the percentage of S phase cells among different groups; G: Statistical analysis of the percentage of G2/M phase cells among different groups. (*p<0.05 versus no VEGF control group).