ObjectiveTo investigate the role of sonic hedgehog (Shh) signal transduction pathway in the expression of vascular endothelial growth factor (VEGF) under hypoxia in cultured human retinal pigment epithelial (hRPE) cells. MethodsARPE-19 were cultured and divided into normal ARPE-19 (Cont) and hypoxia group (100 μmol/L CoCl2 Cobalt Chloride +ARPE-19); hypoxia group was further divided into CoCl2 group, cyclopamine group (CYA) and dimethyl sulfoxide (DMSO) group. 20μmol/L cyclopamine was added to the CYA group 1 hour before hypoxia, 1‰DMSO was added into DMSO group at the same time. The hRPE cells were cultured under hypoxia for 4, 8, 12, 24 hours. The expression of Shh and VEGF were determined by Real-time fluorescent quantitate PCR (RT-PCR). The amount of VEGF in the hRPE-conditioned supernatant was measured using enzyme linked immunosorbent assay (ELISA) at 4, 8, 12, 24 hours, respectively. ResultsRT-PCR tests showed that the level of Shh and VEGF of hRPE was time dependently increased (Shh: F=45.260, P=0.001; VEGF: F=264.938, P=0.001). The level of Shh and VEGF of hRPE in the group treated with cyclopamine was decreased (P < 0.01). ELISA tests showed that the amount of VEGF in hRPE supernatant was significantly increased in time-dependent manner (F=3 156.676, P=0.001), and it was down-regulated by cyclopamine under hypoxia (P < 0.01). ConclusionShh signal transduction pathway could play a role in the VEGF expression induced by hypoxia in hRPE cells.
ObjectiveTo observe the expression of CD147, matrix metalloproteinases-2 (MMP-2) and vascular endothelial growth factor (VEGF) in a rat model of oxygen induced retinopathy (OIR). MethodsEighty-four neonatal Wistar rats were divided into two groups randomly, the hyperoxia group (n=42) and the control group (n=42). Oxygen induced retinopathy was established in the hyperoxia group, the control group was raised in room air. Wholemonts were prepared from postnatal day (p) 7 and 14 rat retina to observe retinal vascular morphology. The number of endothelial cells to break through the internal limiting membrane was counted from p14 retinal paraffin sections. Expression of CD147, MMP-2 and VEGF protein levels was analyzed by immunohistochemistry on p12, p14, and p16 retinal sections. At the meantime, correlation between CD147 and MMP-2, VEGF was analyzed by two-way analysis of variance (ANOVA) test. ResultsAt p7, the retinal vasculature of the control group was radial distributed with large caliber. In OIR group, there were vasoconstriction, large area of avascular zone and a few small areas of vascular network. At p14, the normal untreated rat had interwoven retinal vasculature, but in OIR group, the retinal vasculature was expanded and tortuous, and forming lots of neovascular cluster in the boundary of the perfusion and non-perfusion regions resulting exudation and hemorrhage. At p14, the endothelial cell nuclei breakthrough the internal limiting membrane was (1.30±1.26) and (19.70±3.56) respectively in control and OIR group, the difference was statistically significant (t=21.813, P<0.01). Immunohistochemical staining showed that CD147, MMP-2, VEGF expression was low in control group but high in OIR group. From p12 to p16, CD147, MMP-2 and VEGF protein expression increased in OIR retinas compared with control samples(p12:t=5.612, 4.122, 4.955; P<0.01. p14:t=11.390, 8.047, 12.176; P<0.01. p16:t=6.355, 4.422, 5.110; P<0.01). ConclusionCD147, MMP-2 and VEGF were highly expressed in the rat model of oxygen induced retinopathy.
Objective To study the relationship between the expression of sonic hedgehog (Shh) and vascular endothelial growth factor (VEGF) in hypoxic human retinal pigment epithelial (hRPE) cells. Methods Cultured hRPE-19 cells (3rd - 6th generations) were used in this experiment. hRPE-19 cells were divided into three groups including the control group, the hypoxia experimental group (100 μmol/L CoCl2) and the inhibition group (pretreatment with 20 μmol/L cyclopamine 1 hour before hypoxia). After culturing for 4, 8, 12 and 24 hours, the mRNA level of Shh and VEGF genes in these cells were measured by fluorescence quantitative polymerase chain reaction, and the protein level of Shh and VEGF in the supernatants were measure by enzyme-linked immunosorbent assay. The relationship between the expression of Shh and VEGF was analyzed by Pearson correlation analysis. Results The control group expressed low levels of Shh and VEGF mRNA/protein. The expression of Shh and VEGF mRNA/protein in the hypoxia experimental group was significantly higher than that in the control group (F=178.364, 183.732, 77.456, 91.572; P＜0.01). The expression of Shh and VEGF mRNA in the inhibition group was significantly lower than that in the hypoxia experimental group (F=68.745, 121.834; P＜0.01). In the hypoxia experimental group, the expression of VEGF protein was positively correlated with the expression of Shh protein (r=0.942, P＜0.05); and the expression of VEGF and Shh mRNA was positively correlated (r=0.970, P＜0.01). However, there was no significant correlation in the expression of VEGF and Shh mRNA in the inhibition group (r=0.915, P＞0.05). Conclusion There is a positive correlation between the expression of Shh and VEGF in hypoxic hRPE cells.