Fasting and refeeding augment the angiogenic activities of endothelial cells. (A) Schematic illustration of the experimental procedure for testing the effects of fasting/refeeding on endothelial angiogenesis. (B) CCK-8 analysis of the proliferation of endothelial cells subjected to fasting by serum deprivation for 24 h (F-24 h), fasting for 24 h and then refeeding in normal serum-containing medium for 24 h (F-24 h + N-24 h), or non-fasting (cultured in normal serum-containing medium) for 24 h (N-24 h) or 48 h (N-48 h). n = 3 per group. (C and D) Representative images of scratch wound healing assay of endothelial cells in different treatment groups (C) and the percentages of migration areas (D). Scale bar: 250 μm. n = 3 per group. (E and F) Representative images of transwell migration assay (E) and the numbers of crystal violet-stained migrated cells (F). Scale bar: 100 μm. n = 3 per group. (G-J) Representative tube formation images (G) and quantification of total tube length (H), loops (I) and branching points (J). Scale bar: 250 μm. n = 5 per group. For (B, D, F, H, I and J): One-way ANOVA combined with Bonferroni post hoc test. *P < 0.05, **P < 0.01, ***P < 0.001.