Figure 3.

Immunocytochemistry of the protein VEGF, showing HepG2 cells (magnification, ×40) following 24 h of treatment with CoCl₂ (100 µM) for induction of hypoxia and/or melatonin (1 mM). (A) Untreated cells (control group). (B) Cells with induced hypoxia. (C) Cells with induced hypoxia treated with melatonin. (D) Cells treated with melatonin alone. (E) Statistical analysis of protein expression of VEGF in the experimental groups. Data are presented as the mean optical density ± standard error, and are shown in arbitrary units. *P<0.05 compared with the control group. ^#P<0.05 compared with cells treated with CoCl₂ alone. H+M, hypoxia and melatonin; M, melatonin; VEGF, vascular endothelial growth factor.