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AIM:To investigate the effect of epigallocatechin gallate(EGCG)on the apoptosis of human retinal pigment epithelium(ARPE-19)cells and its mechanism. METHODS:The ARPE-19 cells were cultured in vitro and treated with 0,40,80 and 160 μg/mL EGCG, respectively. At the proposed time of treatment the morphological changes were detected by hoechst 33258 staining. The apoptosis rate was detected by flow cytometry. The expression of apoptosis-related factors B lymphocytoma-2 gene(bcl-2), BCL2-Associated X protein(Bax),caspase-3 and p53 were detected by quantitative RT-PCR and Western blotting.RESULTS: Hoechst 33258 staining showed that the ARPE-19 cells with the increase of EGCG drug concentration, the number of apoptotic cells gradually increased and the apoptotic bodies were observed. Flow cytometry showed that the apoptosis rate increased gradually with the increase of EGCG drug concentration. The apoptosis rates at 40, 80 and 160 μg/mL were 4.95%±0.071%, 11.75%±0.075% and 21.25%±0.919% respectively, which was significantly different compared with the control group(2.8%±1.556%)(P<0.01), presented with a drug concentration-dependent. The results of quantitative PCR and Western blotting showed that EGCG could significantly up-regulate the expression of apoptosis-promoting factors Bax, caspase-3 and the mRNA and protein expression of p53, and down-regulate the apoptosis-inhibiting factor bcl-2, all of these showed concentration-dependent effects.CONCLUSION:EGCG can obviously induce the apoptosis of ARPE-19 cells. The mechanism is related with the inhibition of bcl-2 and increase the expression of Bax, caspase-3 and p53.
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@#AIM: To research the protection of Mcc950, the inhibitor of NLRP3, against the inflammatory injury to human retinal pigment epithelium cell line ARPE-19. <p>METHODS: Cultured cell line ARPE-19 was divided into control group, H<sub>2</sub>O<sub>2</sub> treating group, Mcc950 treating group and Mcc950+H<sub>2</sub>O<sub>2</sub> treating group. Different concentrations of H<sub>2</sub>O<sub>2</sub> and Mcc950 were used to treat the cells. Cell activity was detected by using CKK8 and proper experimental concentration of H<sub>2</sub>O<sub>2</sub> and Mcc950 were determined. After the treatment, the concentration of IL-1β were detected by using ELISA. The change of NLRP3 related proteins were detected by Western blot. And cell apoptosis was examined by TUNEL stain. <p>RESULTS: Cell ability was gradually decreased along with the increasing treating concentrations of H<sub>2</sub>O<sub>2</sub>. Cell ability showed statistical difference when the concentration of H<sub>2</sub>O<sub>2</sub> arrived 400μmol/L. With the concentration of 0.1 and 1μmol/L, Mcc950 had no effect on cell ability. So we chose 400μmol/L H<sub>2</sub>O<sub>2</sub> and 1μmol/L Mcc950 as the experimental concentrations. Compared with the normal control group, the cell viability in the H<sub>2</sub>O<sub>2</sub> treating group was significantly reduced, the IL-1β in the supernatant was significantly increased, and the apoptosis rate was significantly increased, with statistically significant differences(<i>P</i><0.05). In Mcc950+H<sub>2</sub>O<sub>2</sub> treating group, cell viability was significantly increased, the IL-1β in the supernatant and the apoptosis rate were significantly decreased(<i>P</i><0.05). By Western blot, after treated with 400μmol/L H<sub>2</sub>O<sub>2</sub>, the IL-1β, NLRP3, pro-caspase1 and caspase1 were obviously increased compared to control group. After treated with Mcc950, the NLRP3 and pro-caspase1 still were at high level, the expression of caspase1 was suppressed, which indicated that Mcc950 effectively inhibited the activation of NLRP3 inflammasome consequently disturbed the formation of caspase1.<p>CONCLUSION: Mcc950 can inhibits the function of NLRP3, leading to increasing of the cell ability and decreasing of the cell apoptosis.
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Objective To research the role of mitochondrial DNA mediate the cultured human retinal pigment epithelium (hRPE) cell apoptosis induced by blue light and the relationship with time.Methods Established the blue light damage model of cultured hRPE cells in vitro with light emitting diode (LED) blue light density of (4.0-±0.5)mW/cm2 adjusted by FL-1D blue light illumination meter,and the illumination time was set as 0,0.5,1,2,4,6,12 and 24 hours,then the cells were grouped according to the illumination time.Immunofluorescence were used to identify the cells;the expressions of caspase-3,cleaved caspase-3,caspase-9,cleaved caspase-9,bax and bcl-2 were detected with Western blot.Quantitative PCR was used to detect the copy number of mitochondrial DNA and PCR was used to detect mitochondrial DNA 4977bp common deletion.Results Immunofluorescence results showed that the RPE65 protein was expressed in the cytoplasm.The expressions of bax were upregulated after illumination for 1 hour,cleaved caspase-3 were upregulated after illumination for 2 hours,caspase-3,caspase-9,cleaved caspase-9 were upregulated after illumination for 4 hours,while the expression of bcl-2 was downregulated after illuminated for 2 hours,with significant differences compared to the normal control group (all at P＜0.05).The copy number of mitochondrial DNA in 0.5,1,2,4,6,12 and 24 hours groups was downregulated,with significant differences compared to the normal control group (all at P＜0.05).The expressions of 4977bp common deletion in 0.5,1,2,4,6,12 and 24 hours groups were increased,with significant differences compared with the normal control group (all at P＜0.05).Conclusions Blue light can cause cell apoptosis,especially mitochondrial apoptosis,in hRPE probably motivated by mitochondrial DNA damage.
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·AIM: To investigate the effect of Ghrelin on oxidative stress induced by high glucose in human retinal pigment epithelium (RPE) cells. ·METHODS: RPE cells were cultured and divided into the negative control group, high sugar group, Ghrelin low dose group ( 10-9mol/L ) and high dose group (10-6mol/L). Cells survival rate were detected by CCK-8 colorimetry, cells oxidative damage were observed by oxygen sensitive fluorescence probe H2DCFDA staning, changes of intracellular reactive oxygen species ( ROS ) were detected by H2DCFDA staining, super oxide dismutase ( SOD) activity and malondialdehyde ( MDA) content were detected by spectrophotometer colorimetry. ·RESULTS: CCK-8 results showed that RPE cells survival rate increased to 54.79%±3.43% and 79.16%±3.29% after treated with 10-9mol/L, 10-6mol/L Ghrelin, the difference was statistically significant compared with high glucose group (41.65%±3.42%)(P<0.05). H2DCFDA fluorescent probe dying showed that Ghrelin reduced ROS generation in RPE cells and decreased oxidative damage cells. Spectrophotometer colorimetric method showed that according to the high sugar group, SOD activity increased and MDA content decreased in Ghrelin group. ·CONCLUSION: Ghrelin could inhibit high glucose - induced oxidative damage in human RPE cells, which has protective effect on the process of the occurrence and development of diabetic retinopathy.
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Background Researches showed that mitochondria and oxidative stress play a crucial role in retinal photochemical injury,but the relationship between the damage of human retinal pigment epithelium (RPE) cell-induced by blue light and light-irradiated time is less studied.Objective The aim of this study was to research the possible mechanism of RPE oxidative damage induced by blue light in vitro.Methods Human RPE cells were isolated from healthy donors and cultured.The cells were divided into the normal control group and the light exposure group.The cells of light exposure group were irradiated using the blue light of (4.0±0.5) mW/cm2 for 0.5,1,2,3,4,5,6,12 and 24 hours,respectively,and the cells of the normal control group were cultured in dark environment.Cellular viability was detected by MTT method,and the ultrastructure change of subcellular organelles in RPE cells was examined under the transmission electron microscope (TEM).The content of reactive oxygen species (ROS) was assayed by flow cytometry for the assessment of oxidative stress reaction.The relative expressions of nicotinamide adenine dinucleotide phosphate (NADPH) mRNA and cyclooxygenase 1 (COX1) mRNA in the cells were detected by real-time fluorescence quantitative PCR to evaluate the mitochondria function.Results The percentages of cellular viability were (100.00±20.00) ％,(95.73±0.89) ％,(94.67±2.56) ％,(84.23±0.16) ％,(78.57±3.09)％,(75.43±2.18)％,(66.13±1.42)％,(53.43±1.91)％ and (47.97±1.36)％ in the normal control group and light exposure for 1-hour,2-hour,3-hour,4-hour,5-hour,6-hour,12-hour and 24-hour groups,respectively,showing a significant difference among the groups (F =172.270,P =0.000),and the percentages of light exposure for the more than 3 hours groups were significantly lower than those of the normal control group (all at P＜ 0.05).The vacuoles-like degeneration,mitochondrial swelling,decreased microvilli were seen under the TEM.The contents of ROS in RPE cells were (14.75±2.49)％,(19.04± 1.02) ％,(22.81 ±3.20)％,(28.75±2.15)％,(33.06±0.96) ％,(40.64±2.11) ％,(48.25±2.50) ％ and (60.44±2.68) ％ in the normal control group and light exposure for 0.5-hour,1-hour,2-hour,3-hour,4-hour,5-hour,6-hour groups,and with significant increases in ROS contents in various light exposure groups compared with the normal control group (all at P＜0.05).The relative expression levels of NAPDH mRNA in the cells were gradually elevated 3 hours after light exposure with the increase of time in comparison with the normal control group (all at P＜0.05),and the relative expression levels of COX1 mRNA in the cells were higher in the light exposure for 2-hour,3-hour,4-hour and 5-hour group compared with the normal control group (all at P＜0.05),and after that the COX1 mRNA levels were gradually declined and were close to the normal level.Conclusions Blue light irradiation for more than 3 hours causes oxidative stress damage of mitochondria in RPE in vitro,and the damage was more obvious after irradiation for 5-6 hours.
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Background Proliferative vitreoretinopathy (PVR):no blood vessels,fibrous membrane cell proliferation occurs retinal surface.The development of specific mechanisms has not been completely clarified,but the retinal pigment epithelium(RPE) and platelet-derived growth factor(PDGF) for the past few years are the research hotspot.Objective To explore the effects of hypoxia on the production of PDGF-BB and proliferation in cultured human RPE (hRPE) cells.Methods In the experimental group,10,15,20,30,40 μmol/L CoCl2 were used to mimic hypoxia environment of hRPE cells,the control group did not add CoCl2 on cultured hRPE cells.By using reverse transcriptive PCR (RT-PCR) and enzyme linked immunosorbent assay(ELISA),the expression of PDGF-BB mRNA and protein was detected,and detected proliferation of hRPE cells by MTT.The cells were divided into 6 groups,different siRNAs were transfected into PDGF-BB siRNA1 group,PDGF-BB siRNA2 group,PDGF-BB siRNA3 group (because PDGF-BB has three different siRNAs,one of which is a valid siRNA),β-actin siRNA group,unrelated sequence siRNA group,only Lip2000 was plused in the blank control group.After transfection of 4-6 hours,except for blank control group,the other five groups were added to PDGF-BB mRNA and protein and its effect on the proliferation of hRPE cells obviously CoCl2 concentrations (15 μmol/L) simulated hypoxia environment of 24 hours,the detection of PDGF-BB mRNA and protein and hRPE cell proliferation rate.Results Neither PDGF-BB mRNA or protein was found in the blank control group.The production of PDGF-BB mRNA and protein in hRPE cells cultured by different concentrations were different,with significant differences among them (F=43.737,P＜0.01;F=54.612,P＜0.05),and the expressions of PDGF-BB mRNA and protein of 15 μmol/L CoCl2 group were more than other groups,with significant differences between the two groups (all at P＜0.05).MTT showed that PDGF-BB protein and hRPE cell proliferation rate in different concentions of CoCl2 groups were different,with significant differences among them(F=95.379,P＜0.01 ; F =63.375,P＜0.05),the expression of PDGF-BB protein was more and hRPE cell proliferation rate was higher in 15 μmol/L CoCl2group than other groups,with significant differences between the two groups (all at P＜0.05),postive correlation was found between PDGF-BB protein and hRPE cell proliferation rate (r =0.994,P＜0.05).The production of PDGF-BB mRNA and protein in the different siRNA transfected groups were different,with significant differences among them (F =156.330,125.650,both at P＜0.01),and the expressions of PDGF-BB mRNA and protein of PDGF-BB siRNA2 group were more than other groups,with significant differences between them(all at P＜0.05).MTT showed that PDGF-BB protein and hRPE cell proliferation rate in different siRNA transfectedgroups were different,with significant differences among them (F =73.131,98.564,both at P＜ 0.01).The expression of PDGF-BB protein was less and hRPE cell proliferation rate was lower in PDGF-BB siRNA2 group than other groups,with significant differences between them (all at P ＜ 0.05),postive correlation was found between PDGF-BB protein and hRPE cell proliferation rate (r =0.996,P＜0.05).Conclusions Proper hypoxia can induce the expression of PDGF-BB,PDGF-BB expression can significantly promote the proliferation of hRPE cells.In the transfection targeting PDGF-BB siRNA,PDGF-BB expression is suppressed,can effectively reduce the value of hRPE cell hyperplasia.
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Background Choroidal neovascularization(CNV)has been descrihed as a main reason of visual loss in a lot of ocular diseases.Researches showed that local hypoxia and retinal pigment epithelial(RPE) cells play an important role in the formation of CNV.A closely relationship of angiopoietin-2 (Ang-2) and angiogenesis has been proved.However,whether the expression of Aog-2 in hypoxic cultured human RPE cells is associated with the pathogenesis of CNV is still below understood.Objective This study was to investigate the effects of hypoxia on expression of Ang-2 in cultured human RPE cells in vitro,and discuss the possible effects of Ang-2 in the formation of CNV.Methods Human RPE cells were cultured and passaged,and 4-7 generation of cells were used in the experiment.The cells were incubated in cultural plate at the density of 5×107 cells/L.The culture medium containing 200 μmol/L CoCl2 was used to establish the hypoxia model of human RPE cells culturecd in vitro for 0.5,1,2,4,6,12and 24 hours,and the RPE cells cultured under normoxia were as controls.Reverse transcription polymerase chain reaction(RT-PCR) was used to detect the expression of Ang-2 mRNA in cultured human RPE cells,and enzymelinked immunosorbnent assay(ELISA) was used to assay the content of Ang-2 protein in supernatant of cultured human RPE cells.Results The survival rate of human RPE cells was 90％ after resoscitation.The fourth generation of cells showed the fusiform with the less pigment in them.The Ang-2 mRNA/β-actin mRNA value in human RPE cells was significantly different among various groups(F=1086.30,P=0.00),The Ang-2 mRN A/β-actin mRNA value in hypoxia cultured for 0.5 hours group began to increase and peaked in hypoxia culture for 4-6 hours group,with the significant differences in comparison with normoxia control group(P＜0.05).The Ang-2 mRNA/β-actin mRNA value decreased to the baseline level at hypoxia for 24 hours.The ELISA analysis showed that the concentration of Ang-2 protein in supernatant of RPE cells showed significant difference among groups(F=1034.00,P=0.00).The concentration of Ang-2 protein increased at hypoxia culture for 0.5 hours and peaked at 6 hours,showing significant differences in comparison with the control group (P＜0.05).Conclusions Hypoxia could significantly up-regulate the expression of Ang-2 in human RPE cells cultured in vitro.Ang-2 expresses highly in the early stage of hypoxia,implying that Ang-2 participates in the formation of CNV.
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Objective To investigate the influence of serial subcultivation on the immunoregulation of retinal pigment epithelialium cells in vitro.Methods Co-culture-systems of HRPE cells with lymphocytes were established in vitro.The expression of Fas on different passages of HRPE cells and the induction of apoptosis on lymphocytes were observed by flow cytometry. Results When co-cultured with lymphocytes,the expression of Fas was tapering and the duration of culture in vitro was significantly correlated with the expression of Fas(the rate of positive cell: r=-0.859,P0.05).Conclusion HRPE cells beyond 3 passages showed a 1ow capability of immunoregulation and were not suitable for seeds cells for HRPE transplantation.
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The proliferating cell nuclear antigen (PCNA) gene expression was blocked and retinal pigment epithelium (RPE) proliferation was inhibited by using antisense oligonucleotides (AS-ODN)mediated by liposome, to find a new genetic therapy of proliferative vitreoretinopathy (PVR). RPE cells cultured in vitro were transfected with synthetic fluorescence labled AS-ODN mediated by liposome-Lipofectamine, and the intracellular distribution and persistence time of AS-ODN were dynamically observed. AS-ODN (0.07, 0.28 and 1.12 μ mol/L and sense oligonucleotides (S-ODN with the same concentrations as AS-ODN) mediated by liposome were delivered to the RPE cells cultured in vitro, and CPM values were measured by 3H-TdR incorporation assay and analyzed statistically by variance by comparison with blank control group.Expression of PCNA mRNA in RPE cells was detected by in situ hybridization after the treatment of different concentrations of PCNA AS-ODN and S-ODN, and the average optic density (AOD) was measured by image analysis system and was subjected to q-test and correlation analysis with CPM.Our results showed that AS-ODN mediated by liposome could quickly aggregate in cellular plasma and nuclei in 30 min and 6 h, and stayed for as long as 6 days. AS-ODN (0.28 and 1.12 μ mol/L) markedly suppressed proliferation of RPE cells in a dose-dependent manner with the difference being statistically significant (P＜0.05 and P＜0.01,repectively) as compared with blank control group. AOD was well correlated with CPM (r=0.975). It is concluded that liposome could increase transfection efficiency of AS-ODN in RPE cells, and AS-ODN could sequence-specifically suppress PCNA mRNA expression and proliferation of human RPE cells.
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Objective To investigate the best protective solution that could maintain the cell activity and prolong the survival time of the human retinal pigment epithelium (hRPE) cells after break away in vitro culture case. Methods hRPE cells (stored in our laboratory) culture in DMEM/F12, added 10% FBS, EGF 20?g/L and bFGF 20?g/L, which had been cultured for more than five generations. When these culture hRPE cells had been confluenced more than 80%, the hRPE cells were harvested and placed into six kinds of protective solutions (balanced salt solution, Quinn's advantage medium, physiological salt solution, 18-amino acid solution, 5% glucose solution, artificial cerebrospinal fluid), then the cells were stained with the Annexin V /FITC, and the numbers of cell death and cell apoptosis were detected with the fluorescence activated cell sorter (FACS). The hRPE cells were in six kinds of protective solutions and were investigated at three different times from 2 hours to 8 hours. Results The result presented as follows: At the room temperature, the hRPE cells in all six kinds of protective solutions occurred necrosis within 30 minutes. To investigate the state at 4℃, in a duration of 2 hours, the apoptosis rate in the group of balanced salt solution was lowest (0.9%); As compared with the group of balanced salt solution, the apoptosis rate of artificial cerebrospinal presented a great difference (P
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The retinoic acid have been demonstrated to modulate the growth and differentiation of several cell types including retinal pigment epithelium.We evaluated the effect of intravitreal infection of retinoic acid on experimentally induced PVR using human retinal pigment epithelium in the rabbit. 35 eyes of rabbit were induced PVR by injecting of human retinal pigment epithelial cells and were divided into three groups; Control group, group 1(retinoic acid 0.05mg/0.1ml DMSO was injected) and group 2(retinoic acid 0.1mg/0.1ml DMSO was injected). The stages of PVR were observed on days 3, 7, 14 and 28. The mean PVR stage progressed in all three groups. The PVR stage in control group is lower than other groups on days 3 and the PVR stage in group 3 is higher than other groups on days 28. In conclusions, intravitreal injected retinoic acid cannot inhibit PVR proliferation on 0.05 and mg/0.1ml concentration and it had toxic effect on retina in 0.1mg/0.1ml concentration. This results may present the lower limit of concentration to use retinoic acid intravitreously.