Objective To observe the influence of cisplan on the expression of B7-H1 in retinoblastoma (RB) cells，and to investigate its mechanism. Methods Human RB cell line HXO-Rb44 cells were treated by 6 different concentrations of cisplan (0.000, 0.375, 0.750, 1.500, 3.000, 6.000 mu;g/ml), and their B7-H1 mRNA expression was determined by the reversetranscription polymerase chain reaction (RT-PCR) and fluorescence quantitative PCR (FQ-PCR); the B7-H1 protein expression was determined by immunofluorescence and flow cytometry. HXO-Rb44 cells were treated by 1.5 mu;g/ml cisplan for 0, 15, 30, 60, 120 min, then the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) was detected by Western blot.Results The expression of B7-H1 mRNA and protein in the 0.375, 0.750, 1.500, 3.000, 6.000 mu;g/ml group were significantly higher than that of the blank control group (F=395.478，112.03; P=0.000）. Western blot showed that cisplan (1.5 mu;g/ml) could activate ERK1/2 by increasing its phosphorylation in HXO-Rb44 cells. After cisplan treatment, the phosphorylation of ERK1/2 increased gradually and reached its peak at 30 min, and then went down gradually.Conclusion Cisplan can promote the expression of B7-H1 and activate ERK1/2 in RB cells.
ObjectiveTo investigate the inhibitory effects of 5-lipoxygenase (5-LOX) on oxygen-induced retinal neovascularization in mice and to explore its possible mechanisms. Methods7-day-old C57BL/6J mice were randomly divided into normal group, oxygen induced retinopathy (OIR) model group, large-dose group, small-dose group and control group with 12 mice in each group. The mice with their mothers were kept in (75±2)% of oxygen environment for 5 days and then returned to normoxia for 5 days to establish the OIR model except for normal group. From postnatal day 12 to 17, the large-dose group and small-dose group received intravitreous injection of 5-LOX at dose of 100 mg/kg and 50 mg/kg respectively, while the control group received the same volume of 1% dimethyl sulfoxide. The mice in the OIR group received no treatment. The number of endothelium cell nuclei breaking through the inner limiting membrane (ILM) was counted on hematoxylin and eosin-stained retinal section. The mRNA expression of 5-LOX, vascular endothelial growth factor (VEGF)-a, VEGF receptor 2 (VEGFR-2) on retinal tissue were detected by reverse transcription polymerase chain reaction (RT-PCR). The protein expression of 5-LOX, VEGF-a, VEGFR-2 and phosphorylation extracellular signal-regulated kinase (P-ERK) 1/2 on retinal tissue were detected by Western blot. ResultsThe number of vascular cell nuclei breaking through the ILM in the large-dose group and small-dose group decreased significantly compared with the OIR group and control group (F=73.390, P < 0.05). The mRNA expression and protein expression of 5-LOX, VEGFa, VEGFR-2 on retinal tissue were decreased significantly in the large-dose group and small-dose group as compared with the OIR group and control group (F=92.668, P < 0.05). The difference of VEGFR-2 protein expression between large-dose group and small-dose group was not significant (F=2.118, P > 0.05). The differences of 5-LOX, VEGF-a, P-ERK 1/2 protein expression between large-dose group and small-dose group were significant (F=86.490, 165.128, 139.424; P < 0.05). ConclusionHypoxia may induce 5-LOX expression in the retina. Retinal neovascularization was significantly inhibited by selective inhibition of 5-LOX.