Figure 1 of Wu, Mol Vis 2010; 16:1864-1873.

Figure 1. The dose-dependent effects of subtoxic levels of hydrogen peroxide on release of interleukin-6 by retinal pigment epithelium cells. Retinal pigment epithelium (RPE) cells (ARPE-19) were plated into 24-well plates. After 24 h incubation, hydrogen peroxide (H2O2, at 0, 10, 30, 60, and 100 µM) was added to the culture and incubated for 24 h. Conditioned culture medium was collected and the amount of interleukin-6 (IL-6) protein in the conditioned medium was determined using the human IL-6 Quantikine enzyme-linked immunosorbent assay (ELISA) kit. IL-6 levels in conditioned culture medium were expressed as pg/ml (mean±standard deviation in triplicate tests). *0.01< p<0.05, **p<0.01, compared with the controls (cells cultured without H2O2).