ABSTRACT
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.
ABSTRACT
BackgroundRetinal pigment epithelial(RPE) cells can secrete platelet-derived growth factor (PDGF) and PDGF receptor(PDGFR).Studies have shown that PDGF plays a key role in the formation of proliferative vitreous retinopathy(PVR). ObjectiveThis study was to investigate the proliferation and apoptosis changes of RPE after blockage of the PDGFR-α expression by antisense oligonucleotide ( ASODN ) in vitro. Methods Human RPE cells strain was cultured in low glucose DMEM with 10％ fetal bovine serum.Logarithmic phase cells were collected and incubated in 96-well plate at the density of 5 × 105 cells/hole.PDGFR-α ASODN was transfected into RPE cells at different concentrations for 48 hours.The cells of the blank control group were regularly cultured without any transfection.The changes of PDGFR-α expression were detected by reverse transcription-polymerase chain reaction(RT-PCR),and the proliferation of RPE was detected by MTT as the A490 value.Hoechst 33258 fluorescence staining was used to determine the apoptosis of RPE.Flow cytometry method (FCM) was applied to detect the change of cell cycle and apoptosis rate of RPE cells. ResultsThe A490 values of RPE cells were 1.45±0.12,1.07±0.06,0.65±0.05 in blank control group,1.0 μmol/L Lipo-ASODN group and 2.0 μmol/L Lipo-ASODN group with the significant difference(P=0.00 ),and that of 1.0 μmol/L Lipo-ASODN group and 2.0 μ mol/L Lipo-ASODN group were significantly lower than the blank control group ( P =0.00,0.00).Hoechst 33258 staining showed that the apoptosis cells were obviously more in Lipo-ASODN group compared with blank control group.PDGFR-α ASODN transfection induced an increase of percentage of RPE cells in G0/G1 phase( F =206.70,P =0.00),and the apoptosis rates in 1.0 μmol/L Lipo-ASODN group and 2.0 μmol/L Lipo-ASODN group were significantly enhanced in comparison with blank control group ( 37.8 ± 1.3 vs 10.5 ± 0.1,61.2 ± 1.9 vs 10.5 ± 0.1 ) ( F =1808.90,P =0.00 ).Expression intensity of PDGFR-α mRNA in RPE cells in Lipo-ASODN groups was lower. ConclusionsBlocking the PDGFR-α expression with ASODN technology can suppress proliferation and induce apoptosis of RPE cells.Intensity of PDGFR-α mRNA expression in RPE cells is ASODN dose-dependent.ASODN targeted to PDGFR-α offers an experimental basis of the gene therapy for PVR.