ABSTRACT
Background Oxidative damage plays an important role in pathogenesis of age-related macular degeneration( AMD ),and its mechanism is the destroy of blood-retinal barrier.Müller cells is a primary component to stabilize the inner barrier of the blood-retina.Researches showed that epidermal growth factor(EGF) can promote the proliferation and migration of animal Müller cells,but less study was found in the effect of EGF on human Müller cells. Objective The present study was to investigate the effects of EGF on the proliferation and migration of human Müller cells and its molecular mechanism. Methods Human Müller cell line MIO-M1 cells were cultured and incubated,and cultured cells were identified using glial fibrillory acidic protein (GFAP),factor Ⅷ,α-smooth muscle actin( α-SMA ),keratin and S-100.Different concentrations of EGF( 0,1,10,30,100 mg/L)was added in freeserum DMEM,and the positive rate of the cells was calculated using 5-bromo-2-deoxyuridine(BrdU) method.The cells were divided into EGF group,H2 O2 group,EGF + H2 O2 group,glucose oxidase ( GO ) group,GO + EGF group,EGF + LY294002+H2O2 group according to the different intervention,and the effects of LY294002 on the proliferation of Müller cells (A590 )were detected by colorimetric assay for cellular growth and survival( MTT assay).The scratch test of Müller cells was used to assess the influence of EGF(0,1,10,30,100 mg/L)on H2 O2-induced damage of human Müller cell.Western blot was used to detect the cell proliferation under the protection of EGF on co-cultured cells using LY294002 and H2O2 and the activation of Akt signal pathways. Results The proliferative rates of the cells were 28.0％,32.9％,39.0％ in 10,30,100 mg/L EGF groups respectively and obviously higher than those in 0,1 mg/L EGF groups (24.5 ％,26.2 ％ ).Under the H2O2 culture,GO culture,respectively,the A570 value of the Müller cell in high concentrations of EGF groups was significantly increased in comparison with lower concentrations EGF groups with the statistical significance among the groups( F=23.582,P=0.000).Compared with EGF+H2O2 group,the A570value of the Müller cells was lowed in EGF+LY294002+H2O2 group.The maximum migration rate of Müller cells was found in 10 mg/L EGF group.Western blot revealed that the presence of H2O2 reinforced the expression of Akt in Müller cells,however,pretreatment with 100 mg/L EGF antagonized the harmful effect of H2O2 on Müller cells.Meanwhile,pretreatment with EGF and LY294002 reduced the expression of Akt in Müller cells. Conclusions EGF can induce the proliferation and migration of human Müller cells with the strongest effect in 10 mg/L.100 mg/L exogenous EGF has a stronger protection to the Müiller cells against H2O2-induced cell damage by activating the PI3KAkt cell survival pathway.
ABSTRACT
Background Growth factor-induced proliferation and migration of retinal pigment epithelium (RPE) cells are the major pathological changes of proliferative vitreoretinopathy (PVR).Arsenic trioxide ( As2O3 ) is an active ingredient of Chinese traditional medicines,which has an inhibition on proliferation and migration of tumor cells.However,it is not clear whether As2O3 could inhibit growth factor-induced proliferation and migration of RPE cells. Objective This study was to explore the effects of As2O3 on epidermal growth factor (EGF)-induced proliferation and migration of ARPE-19 cells. Methods RPE cell line (ARPE-19 cells) were cultured.Different concentrations of As2O3(0,0.5,1.0,2.0,5.0,10.0,20.0 μmol/L) were added in the culture plate to treat ARPE-19 cells with or without 10 mg/L EGF in serum-free group for 24 and 48 hours,respectively.The MTT colorimetric assay was used to check the cell viability and evaluate the drug toxicity.The effects of As2O3 on EGF-induced proliferation of ARPE-19 cells were analyzed to get an effective and avirulent concentrations of As2O3.The effects of As2O3 on EGF-induced migration of ARPE-19 cells were observed by scratch-wound assay and the Boyden chamber assay.Results MTT assay showed that the A values were gradually declined with the increase of As2O3 concentrations after As2O3 treatment without EGF for 24 hours and 48 hours ( Fgroup =38.269,P =0.000 ; Ftime =0.874,P =0.358 ).Compared with the control group,no significant differences were seen in the A values of ARPE-19 cells in 0.5-5.0 μmol/L groups (all P＞0.05).Meantime,As2O3 reduced the A values of ARPE-19 cell with 10 mg/L EGF in dose- and time-dependent manner ( Fgroup =152.155,P =0.000 ; Ftime =51.649,P =0.000 ).There were not significant differences in 10 mg/L EGF-induced cell growth after 0.5,1.0,2.0 μmol/L As2O3 was added for 24 and 48 hours ( Fgroup =2.215,P =0.126 ;Ftime =2.230,P =0.155).However,when 5.0-20.0 μmol/L As2O3 added,the A values of 10 mg/L EGF-induced ARPE-19 cells lowed,showing a significant difference in comparison with the control groups ( all P＜0.05),with the cellular inhibiting rate 12％,32％,37％ in 24 hours and 39％,44％ and 53％ in 48 hours.Scratch-wound assay showed that EGF-induced horizontal migration of ARPE-19 cells was slow after 0.5-2.0 μmol/L As2O3 treated,and the same results also appeared in cell lognitudinal migration by Boyden chamber assay,with the inhibitory rates 22％,33％ and 46％ respectively. Conclusions As2O3 is avirulent on ARPE-19 cells within definite concentration range.At ≤ 2.0 μmol/L concentrations,As2O3 dose not affect EGF-induced proliferation of ARPE-19 cells,but it suppresses EGF-induced cell migration.At ≥ 5.0 μmol/L concentrations,As2O3 plays an inhibitory role to EGF-induced proliferation of ARPE-19 cells.