Effect Of PGC-1α On Development Of Retinal Neovascularization In The Mouse

Chapter one:The expression of PGC-la in oxygen-induced retinopathy in miceObjective:To observe the expression of PGC-la in retina of oxygen-induced retinopathy(OIR) in mice,and investigate the effect of PGC-la in a murine model of OIR.Methods:76C57BL/6J mice were exposed to (75±2)%oxygen for5days,and then returned to room air condition 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, retinal PGC-1α mRNA and protein levels were determine by Real-time PCR and western blot methods at postnatal days(P):12(0h),12(3h),12(6h),13,14,17and26.Results:In the hypoxic group of fluorescence angiograms, neovascular tufts and fluorescein leakage were observed surrounding the non-perfused areas. On the contrary, the blood vessel were uniformly distributed and without non-perfused areas or fluorescein leakage in normal group.The mean neovascular nuclei protruding into the vitreous body in hypoxic group were24.46±3.47,compared to the normal group were0.05±0.24. There were signincant increases in both retinal PGC-1α mRNA and protein levels in the hypoxic group at P14and P17.Conclusions:PGC-la level was highly expressed in murine retina under hypoxia and may be one regulator in inducing retinal neovascularization.Chapter two:Inhibitory effect of small interfering RNA targeting PGC-la on retinal neovascularization in miceObjective:To assess the inhibitory effects of small interfering RNA (siRNA) targeting PGC-1α on retinal neovascularization in mice.Methods:On P7C57BL/6J mice were exposed to(75±2)%oxygen for5days,and then returned to the room air condition to induce retinal neovoscalarization. Liposome mediated PGC-la siRNA complex was injected into the vitreous of OIR model mice.The expression of PGC-1a and VEGF were identified by immunofluorescence. Fluorescein angiography was used to evaluate the vascular morphology. The proliferative neovascular was quantified by counting the nuclei of new vessels extending from retina into the vitreous. PGC-1α and VEGF levels in retina were measured by Real-time PCR, Western blot and Immunohistochemical methods.Results:The expression of PGC-la mRNA and protein in retina were increased in control model group and compared with normal group, while decreased46.76%and47.67%respectively in PGC-1α siRNA group.VEGF mRNA and protein in retina were increased in control model group, decreased48.84%and44.44%respectively.Furthermore, PGC-la siRNA reduced RNV and neovascular nuclei.Conclusions:PGC-la siRNA can inhibit retinal neovascularization effectively in the mouse. Therefore, PGC-1α siRNA interference techniques could supply a powerful herapeutic tool for treating ischemia-induced retinal diseases.