Zeaxanthin Inhibits Hypoxia-Induced VEGF Secretion by RPE Cells through Decreased Protein Levels of Hypoxia-Inducible Factors-1α

Figure 7

Effect of zeaxanthin on HIF-1α protein levels in RPE cells under hypoxia. RPE cells were seeded into 6 cm culture dishes at a density of cells per well. After 24 h, zeaxanthin was added at 50, 100, and 150μM concentrations. One hour later, cells were incubated under 1% O₂ (a) or cultured with CoCl₂ at 150μM (b). Cells cultured under normoxic condition and without zeaxanthin served as negative controls. Cells cultured under hypoxia and without zeaxanthin served as positive control. Cells were collected 24 h later; HIF-1α protein levels in cell extracts were determined by using the Intracellular HIF-1α ELISA kits and expressed as percentages of negative control (, ). Zeaxanthin significantly inhibited hypoxia-induced accumulation of HIF-1α protein. , compared with the negative controls. ⁺, compared with the positive controls.

(a)

(b)