Figure 5. Retinal neuroprotective effect of cannabidiol (CBD) in experimental diabetes. A: Representative images show the terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) labeling of frozen eye sections from the diabetic rats (eight weeks) in different retinal layers. TUNEL-positive cells (arrows) were distributed mainly in the inner retinal layers. B: Statistical analysis of TUNEL-positive nuclei in various groups. At least four fields per mid-peripheral retina were counted for each retina from one animal. (n=4–5 retinas/group, *p<0.05, versus control [standard error of mean]). Treating the diabetic animals with CBD (10 mg/kg/2 days, i.p.) prevented neuronal death. C: Representative images show the localization of the apoptotic marker caspase-3 in the ganglion cell layer and the inner retinal layer in diabetic retina sections but not in other groups. D: Enlarged window of retina sections showing colocalization (yellow) of the apoptotic marker caspase-3 (green) within the retinal ganglion cell layer labeled with Brn-3 (red). The layers shown are the ganglion cell layer (GCL), the inner plexiform layer (IPL), the inner nuclear layer (INL), and the outer nuclear layer (ONL).