Figure 2. Apoptosis was evaluated by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL). Oxidative stress was induced by exposing the retinal ganglion cells (RGCs) to 20 μM of H₂O₂ for 16 h. In the maltol treatment group, 1 mM of maltol was added to culture medium at the time of injury. A: Undamaged control; B: Oxidative stress only; C: Oxidative stress with maltol treatment. Apoptotic cells showed broken nuclei with green fluorescence over counterstained, unfragmented nuclei with orange-red fluorescence. Scale bar is 200 μm. D: The proportion of apoptotic cells was expressed as mean ± standard error of the mean (SEM). Asterisks, p<0.05, n=12, *Significant difference between control versus oxidative stress with/without maltol treatment, **Significant difference between oxidative stress without versus with maltol treatment.