Figure 4. Apoptotic DNA characteristics of corneal endothelial cells visualized with TUNEL staining. Cells were incubated either in the absence of mitomycin C for 15 h and 24 h (control, A) or in the presence of 0.001 mg/ml MMC for 24 h (B) and 0.01 mg/ml mitomycin-C for 15 h (C). The typical positive DNA apoptosis was clearly stained following exposure to mitomycin C. After exposure of cells to 0.001 mg/ml mitomycin C, cellular chromatin condensed and marginalized at the nuclear membrane. After exposure to 0.01 mg/ml mitomycin C, cells were seriously damaged and formed typical apoptotic bodies containing cytosol, condensed chromatin, and organelles. Each bar represents 3 μM. Two other independent experiments produced similar results.