Figure 1. Impedance measurements on retinal pigment epithelium (RPE) cells as a function of time. Cultured adult human retinal pigment epithelial (ARPE19) cells were plated in chambers containing gold electrodes, and impedance measurements were made at fixed time intervals for 24 h. The epigallocatechin gallate (EGCG) inhibited ARPE19 cell migration, even without the presence of platelet-derived growth factor (PDGF)-BB. For the cells treated with 20 ng/ml PDGF-BB, the impedance increased faster and was significantly higher at 24 h than the cells treated without 20 ng/ml PDGF-BB (p<0.05) or with 10 μM EGCG (p<0.05). The experiment was performed four times with similar results. Each value represents the mean of four replicates.