Figure 9. TUNEL labeling of rat retinal sections. A: Representative fluorescence microscopic images of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL; green), counterstained with 4′, 6-diamidino-2-phenylin-dole (DAPI; blue) for cellular nuclei. White arrows indicate TUNEL positive cells. Magnification = 400X. Scale bar = 50 µm. B: Quantification of TUNEL positive cells. Data are mean ± standard error of the mean (SEM, n=3). C, control; D, diabetes; D+B12, diabetic rats treated with vitamin B₁₂. *Significant difference from the control group (p<0.05).