Protective effect of epidermal growth factor on proliferation and migration of the human Müller cell from oxidative damage / 中华实验眼科杂志

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.