Figure 2. Promotion effects of TCS-401 on the proliferation of rat RPE cells in vitro. A: Proliferation of RPE cells was determined with MTT after 24 h incubation with concentrations of 0.5, 1, and 2 μM TCS-401. The 0.5, 1, and 2 μM TCS-401 treatment increased the proliferation of RPE cells. *p<0.05, compared to the control group. B-D: Contact-inhibited RPE cells were incubated with 0.5, 1, and 2 μM TCS-401 for 24 h, and levels of cyclin A and cyclin D1 were determined with western blot analysis, respectively. The 1 and 2 μM TCS-401 treatment promoted cell cycle progression. The data represent the mean±standard deviation of three independent experiments. *p<0.05, compared to the control group. MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetracolium bromide; RPE, retinal pigment epithelium.