Purpose: Resveratrol, a polyphenolic phytoalexin present in red wine, has a protective role against tumor-induced angiogenesis. Exudative age-related macular degeneration is characterized by hypoxia-induced choroidal vascular endothelial cell (CVEC) proliferation. In this study, we evaluated the effect of resveratrol on hypoxic CVECs and the underlying signaling pathways involved.
Methods: CVECs (RF/6A) after induction of hypoxia with cobalt chloride (CoCl2, 200 μM) were exposed to increasing doses of resveratrol (2, 4, 6, 8, 10, and 12 μg/ml). Cell viability was measured with 4-[3-(4Iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1, 3-benzene disulfonate (WST-1) colorimetric assay. The effect of resveratrol on hypoxia-induced vascular endothelial growth factor (VEGF) release was analyzed with enzyme-linked immunosorbent assay. The mechanistic pathway was further evaluated by analyzing phosphorylated stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) using immunoblot and cleaved caspase-3 with In-Cell enzyme-linked immunosorbent assay.
Results: Resveratrol inhibited hypoxic CVEC proliferation. Hypoxia-induced VEGF release (30.9±2.6 pg/ml) was inhibited in a dose-dependent fashion by 2, 4, 6, 8, 10, and 12 μg/ml resveratrol to 12.4±2.1, 11.0±1.9, 10.3±3.0, 7.5±1.9, 5.5±2.0, and 5.5±2.3 pg/ml, respectively. SAPK/JNK increased by 1.8-fold and 3.9-fold after treatment with 4 and 12 μg/ml resveratrol, respectively. Significant increase in caspase-3 levels was observed with 12 μg/ml resveratrol.
Conclusions: Our study demonstrates that resveratrol suppresses hypoxic CVEC proliferation through activation of the SAPK/JNK pathway. Resveratrol, a nutritional supplement and inhibitor of CVECs, may be a useful adjunct to current anti-VEGF therapy in wet age-related macular degeneration.