[Changes of protein kinase C for the proliferation of retinal pigment epithelium cells induced by subretinal fluid].
OBJECTIVE
To study the effects of subretinal fluid (SRF) on the proliferation of retinal pigment epithelium (RPE) cells and on the activation and translocation of protein kinase C (PKC); to investigate the relationship between the proliferation and the changes of PKC in the RPE cells; and to study the effect of PKC inhibitor.


METHODS
RPE cells were harvested to measure the PKC activity in cytoplasm and cellular membrane after being treated with subretinal fluid (SRF) obtained from PVR patients with different degrees (B grade and C), PKC specific activator PMA (positive control) or normal vitreous. RPE cells cultured with DMEM culture medium only were used as the negative controls. PKC activity in cytoplasm and cellular membrane was measured with radioactive isotope (32)P label method. For further study, the PKC specific inhibitor N, N-dimethyl was used to pretreat the RPE cells before the administration of SRF, PMA or normal vitreous, and then the activity of PKC was observed and recorded. (3)H-TdR was used to measure the proliferation of RPE cells with or without the activation and translocation.


RESULTS
SRF and PMA could promote the proliferation of RPE cells and activate PKC in the cytoplasm of RPE cells, and then promoted the PKC translocated from the cytoplasm to cellular membrane. The peak of PRC on the cell membrane appeared later in cells treated with SRF when compared with those treated with PMA. The appearance of peak of PKC in cells treated with SRF from grade B PVR was later than those treated with SRF from grade C PVR, the stimulating effect on the proliferation of RPE cells by the SRF B was also less than those from the SRF C. No activation of PKC and increased proliferation were observed in RPE cells treated with normal vitreous or DMEM culture medium. Pre-treatment with PKC inhibitor could block the PKC-activating effects and proliferation-stimulating effects of SRF and PMA on the RPE cells, therefore no significant difference could be detected between different groups.


CONCLUSIONS
SRF can promote the proliferation of RPE cells and induce the activation and translocation of PKC in RPE cells. PKC is involved in the process of the proliferation of RPE cells. The PKC inhibitor could block this process.
Sun
Zhao-yi
ZY
Department of Ophthalmology, the First Affiliated Hospital of China Medical University, Shenyang 110001, China.
Hong
Jing
J
D000328:Adult; D049109:Cell Proliferation; D002478:Cells, Cultured; D006801:Humans; D010857:Pigment Epithelium of Eye / Q000201:enzymology / Q000473:pathology*; D011493:Protein Kinase C / Q000378:metabolism*; D012160:Retina / Q000378:metabolism; D018630:Vitreoretinopathy, Proliferative / Q000201:enzymology / Q000473:pathology
D011493:Protein Kinase C