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 (20min-1h), while the protein expression levels of cPKCα and γ were markedly elevated in the delayed retinal IPC (12–168h) of rats. The increased protein expressions of cPKCα at 72h and cPKCγ at 24h 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.