| Chapter one:The expression of caveolin-1 in oxygen-induced retinopathy in miceBackground/Aims Recent researches have shown that caveolin-1 may promote neovascularization. We evaluate the expression of caveolin-1 during retinal neovascularization in a murine model of oxygen-induced retinopathy.MethodsC57BL/6J mice were exposed to 75±2% oxygen for 5 days and returned to room air to induce retinal neovascularization. Retinal neovascularization was observed by fluorescence angiography and was quantified by counting the endothelial nuclei protruding into the vitreous cavity after Hematoxylin-eosin staining. RT-PCR and western blot analysis were used to determine retinal caveolin-1 mRNA and protein levels at postnatal days (P) 13,15, and 17. The blood-retina barrier was evaluated by western blot analysis of extravasated albumin in the retina.Results In fluorescence angiograms, irregular neovascularization and fluorescein leakage were observed surrounding the unperfused areas in the hypoxic group. The hypoxic group had, on average,50.70±4.56 neovascular nuclei protruding into the vitreous body, while similar nuclei was 0.05±0.14 in the control group. Compared to the normoxic group, there were significant increases in both retinal caveolin-1 mRNA and protein levels in the hypoxic group at P13,15, and 17. Caveolin-1 expression increased during hypoxia and overexpression of caveolin-1 also correlated with the appearance of extravascular albumin.Conclusion Caveolin-1 level increases in murine retina under hypoxia and may be one regulator in inducing retinal neovascularization.Chapter two:Inhibitory effect of caveolin-1 shRNA on retinal neovascularization in oxygen-induced retinopathy in miceObjective Caveolin-1 expression correlates with permeability of endothelial barriers and angiogenesis. However, the role of caveolin-1 in retinal hyperpermeability and retinal neovascularization (RNV) remains unknown. We evaluated the effect of caveolion-1 shRNA on the blood-retina barrier and RNV in a murine model of oxygen-induced retinopathy.Methods On postnatal day (P) 7, mice were exposed to 75±2% oxygen for 5 d and then returned to room air to induce RNV. RNV morphology was studied by fluorescence angiography and was quantified by counting the endothelial cell nuclei protruding into viteous cavity. The blood-retina barrier was evaluated by western blot analysis of extravasated albumin in the retina. RT-PCR and western blot analysis were used to examine retinal expression levels of caveolin-1 mRNA and protein. Caveolin-1 shRNA was injected intravitreally in the OIR models. The expression of caveolin-1 mRNA and protein, and RNV were assessed as described above.Results Caveolin-1 mRNA and protein expression increased during retinal neovascularization and overexpression of caveolin-1 correlated with the appearance of extravascular albumin.Caveolin-1 shRNA reduced caveolin-1 mRNA and protein levels by 47.94% and 54.76%, respectively. Furthermore, caveolin-1 shRNA reduced RNV by 51.3% and reduced albumin leakage by 56.32%.Conclusion Caveolin-1 levels are increased in hypoxic murine retinas and may play an important role in inducing retinal neovascularization. Caveolin-1 shRNA can inhibit experimental retinal hyperpermeability and neovascularization. Therefore, caveolin-1 RNA interference techniques could be a powerful and novel therapeutic tool for treating ischemia-induced retinal diseases. |
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