The changes of protein kinase C for human retinal pigment epithelium and retinal glial cells proliferation induced by the subretinal fluid

AIM: To study the effect of the subretinal fluid (SRF) on proliferation of retinal pigment epithelium (RPE) cells and retinal glial (RG) cells and associated activation and translocation of protein kinase C (PKC) as well as the application of PKC inhibitor. METHODS: RPE and RG cells were disintegrated to obtain PKC activity of cytoplasm and cellular membrane after being treated by the subretinal fluid (SRF) from the different stages of PVR patients (grade B and C) or being treated with PKC specific activator [phorbol-12-myris-tate-13-acetate (PMA)] or normal vitreous or DMEM culture medium. PKC activity in cytoplasm and cellular membrane was measured using radioactive isotope (32)P labeling in a specific reaction of phosphorylation on PKC substrate. In addition, the PKC inhibitor, dequalinium chloride, was used to pretreat the RFE and RG cells before the cells exposed to SRF or PMA or normal vitreous. 3H-TdR (tritiated thymidine) was used to measure the levels of proliferation of RPE and RG cells with or without the activation and translocation. RESULTS: SRF and PMA promoted the proliferation of RPE and RG cells. SRF and PMA activated PKC in the cytoplasm of RPE and RG cells and the activated cytoplasm PKC translocated to the cellular membrane of RPE or RG cells. The cell proliferation or PKC activation or translocation was not equally active in RPE as in RG cells. However, PKC inhibitor which attenuated the cell proliferation did not show significant difference on inhibition of RPE and RG cell proliferation(P> 0.05). CONCLUSION: SRF can lead to the activation and translocation of PKC in RPE and RG cells, which promote the proliferation of RPE and RG cells. Dequalinium chloride can inhibit PKC activation and translocation hence slow down the cells proliferation.