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AlM:To evaluate the expression of transcriptional factor lslet-1 in retina in experimental retinal neovascularization induced by oxygen. METHODS: The murine retinal neovascularization were induced by hyperoxia exposure. The morphological observation of retinal neovascularization was performed using angiography by fluorescein dextran injection under the fluorescence microscope, and the new blood vessels were quantified after 5d in room air (17-day-old) by counting the vascular epithelial cell nuclei protruding into viteous cavity using HE stain. Realtime PCR and Western blot were used to examine retinal lslet-1 level in postnatal 7,12, 14,17 and 26d respectively. RESULTS: A lots of new blood vessels were demonstrated in the mouse retina in hyperoxic group by fluorescein angiography and histological method. Moreover, no significant difference was found in retinal lslet-1 level in postnatal 7d between hyperoxic group and control group, but was significantly higher in postnatal 12, 14 and 17d mice compared with control mice. However, mice at postnatal 26d, expression of lslet-1 in retina decreased to normal level. CONCLUSlON: ln processing mouse model of retinal neovascularization, sustained hypoxia retinal tissue induce retinal neovascularization by increas the expression of transcription factor lslet-1.
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BackgroundHypoxia-inducible factor-1 α (HIF-1α) specific double-stranded RNA ( dsRNA ) mediated by liposome inhibit reinal neovascularization in mice at dose-dependent manner. ObjectiveThe present study was to investigate the inhibitory effect of dsRNA targeting HIF-1α on retinal neovascularization in mice.MethodsModels of oxygen-induced retinal neovascularization were set up in C57BL/6J mouse through exposure of postnatal day 7 ( P7 ) to (75±3) ％ oxygen for 5 days.Fluorescein conjugated Dextran angiography of retinal vascular was performed to identify the retinal neovascularization.The 8 mice of the normal group were raised in the room air.Fifty-one P7 mice exposed to(75±3)％ oxygen for 5 days and then returned to the room air and assigned to control group ( 3 mice),empty vector group( 3 mice) and gene therapy group (45 mice),and the latter were medially divided to 9 groups randomly according to dose-ratio ( liposomes ∶ plasmid).The pSilencer 2.1-U6 hygro was injected in the model mice of empty vector group,and different dose-ratios of pSilencer2.1-U6 hygro-HIF-1α dsRNA were injected respectively in the model mice of various gene therapy groups.Fluorescein conjugated Dextran angiography of retinal vascular was performed to observe the morphology of new blood vessels,and retinal slides were prepared to score the numbers of nuclei extending beyond the inner limiting membrane( ILM ),and expression of vascular endothelial growth factor(VEGF) was detected in the retina by immunohistochemistry.Results The retinal blood vessels of the normal group formed a fined radial branching pattern.The retinal vascular patterns in the control group and the empty vector group were characterized by decreased central perfusion in both the superficial and the deep layers.The abundant vessels were distorted and irregular in the control group and empty vector group,and the obstructed capillary and lots of neovascular tufts were seen.The retinal neovascularization and non-perfusion distraction in the every gene therapy group were reduced markedly with the most severe appearance in 1 ∶ 1 ( liposomes ∶ plasmid) dose-ratio group.Few vascular endothelial cell nucleus extending beyond the ILM were found in the normal group;while a large number of vascular endothelial cell nucleus were showed in the control group and empty vector group with the occurring rate 100％.Statistically,no significant difference was seen in the number of nuclei extending beyond the ILM between the control group and the empty vector group(11.57±5.85 vs 11.53±6.15),however,that in 1∶1 (liposomes∶plasmid) group was reduced markedly ( 2.17 ± 4.23 ) ( P ＜ 0.01 ).Immunohistochemistry revealed that VEGF was faintly expressed in the normal group but strongly expressed in the control group and the gene therapy group.VEGF expressions of various gene therapy groups were weaker than ones of the control group and the empty vector group.ConclusionsRetinal neovascularization can be efficiently inhibited by intravitreal injection of the pSilencer2.1-U6 hygro-HIF-1α dsRNA mediated by liposome.Proportion of 1 ∶ 1 (liposomes ∶ plasmid)has a maximized efficiency.
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<p><b>OBJECTIVE</b>To study the inhibition effect of HIF-1α specific siRNA expression vector pSUPERH1-siHIF-1α on retinal neovascularization in a mouse model of retinopathy of prematurity (ROP).</p><p><b>METHODS</b>The mouse model of ROP was prepared by the method Smith described. Forty-eight ROP mice were randomly divided into two groups: an experimental group that was intravitreously injected with pSUPERH1-siHIF-1α and a control group that was injected with pSUPER retro vector. The levels of HIF-1α and vascular endothelia growth factor (VEGF) in the retina were examined by Western blot. The retinal neovascularization was evaluated by angiography using FITC Dextran and quantitated histologically.</p><p><b>RESULTS</b>The levels of HIF-1α and VEGF in the retina in the experimental group were reduced 90% and 65% respectively compared with those in the control group. Meanwhile, the number of retinal neovascular endothelial nucleus outbreaking the inner limit membrane in the experimental group was significantly reduced compared with that in the control group.</p><p><b>CONCLUSIONS</b>The development of retinal neovascularization of ROP can be markedly inhibited by RNA interference targeting HIF-1α.</p>