Figure 3. PKC immunoreactivity in the retinal arteries and neuroretina. Representative examples showing phosphorylated PKCα, PKCβ1, and PKCβ2 immunoreactivity in the retinal arteries and retina following ischemia and 20 h of reperfusion. A: Double staining with CD31 (also called PECAM-1), an endothelial cell marker, showed co-localization of phosphorylated PKC in the endothelium (arrows). Weak phosphorylated PKC staining could also be seen in the smooth muscle layer. B: The lower levels of PKCα, PKCβ1, and PKCβ2 observed in the neuroretina after ischemia–reperfusion, according to western blot, were reflected in the immunofluorescence staining results, showing less staining for phosphorylated PKCα and PKCβ2 in the ischemia–reperfusion eyes compared to sham-operated eyes. Furthermore, the phosphorylated PKCβ1 staining showed fewer labeled bipolar cells bodies in the eyes subject to ischemia-reperfusion compared to sham-operated eyes (see insert in the p-PKCβ1 picture). Similar results were seen in all pigs studied. Abbreviations: outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), ganglion cell layer (GCL), and nerve fiber layer (NFL).