Figure 6. Effects of epigallocatechin gallate (EGCG) on PDGFR-β, PI3K, and MAPKs phosphorylation in human retinal pigment epithelium (RPE) cells. Platelet-derived growth factor-BB (10 ng/ml) was preincubated with a vehicle or 1, 3, and 10 μM of EGCG for 30 min and then added to human RPE cells. Western blotting was used to analyze PDGFR-β, PI3K, and MAPKs phosphorylation. All concentrations of EGCG at or above 3 μM significantly inhibited PDGF-BB-induced PI3K/Akt, ERK1/2, and p38 phosphorylation in human RPE cells in a concentration-dependent manner. However, there was no effect of PDGF-BB and EGCG on c-Jun N-terminal kinases (JNK) phosphorylation. The results presented are representative of four independent experiments.