Figure 8.

Apoptosis in the diabetic retina. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells were observed in the ganglion cell layer (GCL) and colocalized with anti-NeuN antibody at 4 and 12 weeks after induction of diabetes (A,C). The percentage of TUNEL-positive cells was higher in diabetic retinas than in the normal control (p = 0.002, p < 0.001) at 4 and 12 weeks, respectively, after onset of diabetes (B,D). The proportion of apoptotic cells in diabetic retinas was reduced by administration of nicotinamide at 4 and 12 weeks after induction of diabetes (p = 0.002, p < 0.001, respectively). Scale bar = 20 μm. DM, diabetes mellitus; NAM, nicotinamide. INL, inner nuclear layer. ONL, outer nuclear layer. *, significantly different as indicated (p < 0.05).