Figure 2. MiR-9 expression in ARPE-19 cells is not affected by oxidative stress. The cells were treated for 24 h with menadione (20 μM) or sodium arsenite (2 μM), agents known to cause oxidative stress. The expression of miR-9 and HMOX1, a marker for oxidative stress, was analyzed using real-time RT–PCR. A: MiR-9 expression was not affected by menadione and arsenite. B:HMOX1 expression was markedly increased, as expected, by both menadione and arsenite. *p<0.05 compared to control, n=4.