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@#AIM: To investigate the effects of simvastatin(Sim)on human retinal pigment epithelial cells(RPE-19)and the possible mechanisms <i>in vitro</i> under hypoxia. <p>METHODS: RPE-19 cells were divided into three group: control group, hypoxia group(the final concentration of CoCl2 in the medium was 125 μmol/L), and Sim treatment group(3 μmol/L Sim was added in the RPE cells' medium which contain 125 μmol/L CoCl2). After 24h, the morphology of RPE-19 cells were observed, the proliferation of cells were calculated by MTT, the secretion levels and protein expression of hypoxia-inducible factor 1-Alpha(HIF-1α)and vascular endothelial growth factor(VEGF)were detected by enzyme-linked immunosorbent assay(ELISA)and Western blotting. The expression level of autophagy protein was detected by Western blot and apoptosis was detected by TUNEL.<p>RESULTS: The morphology and activity of RPE-19 cells showed an apparent change under hypoxia. The expression of HIF-1α and VEGF protein were increased obviously in the hypoxia group and then significantly decreased after Sim treatment. Beclin1, and LC3B proteins were decreased in the CoCl2+Sim group, and the expression levels were lower than the control and CoCl2 group. Under hypoxia, Sim inhibited RPE cells' proliferation and promoted the apoptosis.<p>CONCLUSION:Sim inhibits RPE cells' proliferation, decreases HIF-1α and VEGF protein, and promotes apoptosis under hypoxia. Our results suggested that the mechanism by which Sim promoted apoptosis in RPE cells may be related to its inhibition of autophagy.
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@#Proliferative vitreoretinopathy(PVR)is a serious complication arisen from ocular trauma, diabetic retinopathy, vascular retinopathy, inflammatory retinopathy and other ocular diseases. It is also the most important reason for the failure of rhegmatogenous retinal detachment surgery, which is a great threat of visual function. A large number of studies have proved that the main risk factor for PVR is the damage of blood-retinal barrier, in which retinal pigment epithelial(RPE)cells are stimulated by cytokines in the vitreous cavity. RPE cells underwent epithelial-mesenchymal transition(EMT), which transformed into fibroblasts. The cell morphology changed, the tight junctions between cells disappeared, the cell polarity lost, and the proliferation, migration, and invasion abilities were enhanced. A contractile fibrous proliferative membrane is formed on the anterior surface or under the retina. The fibrous proliferative membrane will lead to the retina folds, pull the retina and lead to retinal detachment, which will eventually lead to vision loss or even blindness. Nowadays, plenty of studies investigating the prevention and treatment of PVR have been carried out at home and abroad. In this review, we briefly illustrated the signaling pathways related to epithelial-mesenchymal transformation in RPE cells and the treatment of PVR.