Figure 4

Proliferation analyses of NPCs under different growth factors. Cells (n = 12) were incubated with MTS reagent for 4 hr and changes in proliferation were studied at five time intervals (24 hr, 48 hr, 72 hr, 96 hr, and 120 hr). The data represented as optical density (OD) at 540 nm in mean ± SEM (p < 0.05).