Determination of conventional protein kinase C isoforms involved in high intraocular pressure-induced retinal ischemic preconditioning of rats

Evidence indicates that conventional protein kinase C (cPKC) plays a pivotal role in the development of retinal ischemic preconditioning (IPC). In this study, the effect of high intraocular pressure (IOP)-induced retinal IPC on cPKC isoform-specific membrane translocation and protein expression were observed. We found that cPKCγ membrane translocation increased significantly at the early stage (20 min-1 h), while the protein expression levels of cPKCα and γ were markedly elevated in the delayed retinal IPC (12-168 h) of rats. The increased protein expressions of cPKCα at 72 h and cPKCγ at 24 h after IPC were further confirmed by immunofluorescence staining. In addition, we found that cPKCγ co-localized with retinal ganglion cell (RGC)-specific marker, neurofilaments heavy chain (NF-H) by using double immunofluorescence labeling. These results suggest that increased cPKCγ membrane translocation and up-regulated protein expressions of cPKCα and γ are involved in the development of high IOP-induced rat retinal IPC.