Figure 2. Quinotrierixin does not induce apoptosis in human retinal pigment epithelium cells. A: ARPE-19 cells were treated with quinotrierixin 0.1 μM, 0.5 μM, or 1 μM for 24 h. Apoptosis was determined with terminal deoxynucleotidyl transferase-mediated uridine 5′-triphosphate-biotin nick end labeling (TUNEL) assay. B: ARPE-19 cells were treated with hydroquinone (HQ) 100 μM as positive control. Red: TUNEL staining of apoptotic cells; Blue: nuclear staining with 4'-6-diamidino-2-phenylindole (DAPI).