Effects of liposome-mediated endostatin gene transfection in vivo on inhibition of experimental choroidal neovascularization in rats / 第三军医大学学报

ABSTRACT

Objective To investigate the effects of liposome mediated intraocular gene transfection of endostatin on the inhibition of the development of choroidal neovascularization (CNV) in a rat model. Methods Experimental CNV model in Brown Norway rats was induced by laser photocagulation. The recombinant eukaryotic expression plasmid pSecTagA hEndostatin or control plasmid pSecTagA and liposome complexes were injected into the subretinal space of the model rats. In situ hybridization and immunohistochemical observation confirmed the presence of endostatin mRNA and protein expression two weeks after injection. Intraocular and serum levels of endostatin were measured by enzyme linked immunosorbent assay. The intensity of fluorescein leakage from the photocoagulated lesions was studied at 13 d after photocoagulation. The area of CNV was measured using high molecular weight FITC dextran (MW2?10 6) for high resolution angiography in RPE choroid sclera flat mounts. In addition, sections of CNV lesions were studied by light microscopy and endoglin (CD105) immunohistochemical evaluation. Results The retina, RPE, choroidal were infected by subretinal delivery of the pSecTag hEndostatin and expressed the endostatin. Two weeks after intraocular injection, the level of endostatin in the whole eye homogenates were (50 14?3 43) ng/eye and (31 5?2 21) ng/eye, respectively. Fluorescein leakage from the CNV lesions decreased significantly as compared with that in the control groups. The average area of CNV at the sites of the Bruch's membrane rupture showed significant difference in eyes injected with endostatin as compared with that in the control eyes. Endothelial cells demonstrated strong immunoreactivity of CD105 in CNV lesions in the control eyes. Conclusion Liposome mediated endostatin gene transfection can significantly inhibit the development of CNV.