A reproducible and quantifiable model of choroidal neovascularization induced by VEGF A165 after subretinal adenoviral gene transfer in the rabbit

摘要

Purpose: To determine the effects of thevascular endothelial growth factor (VEGF)-A165 deliveredusing a high capacity adenoviral vector (HC Ad.VEGF-A) on vasculargrowth and pathological changes in the rabbit eye. To combine differentdetection methods of VEGF-A165 overexpression-inducedneovascularization in the rabbit. Methods: HC Ad.VEGF-A165 wasconstructed and injected at 5x106 infectious units into thesubretinal space of rabbit eyes. Two and four weeks postinjection, thedevelopment of neovascularization and the expression of HCAd-transduced VEGF-A165 protein were followed up in vivo byscanning laser ophthalmoscopy, fluorescein and indocyanine greenangiographies and ex vivo by electron microscopy andimmunohistochemistry Results: We observed a choroidalneovascularization (CNV) with leakage in 83% of the rabbit eyes. Ourfindings present clear indications that there is a significant effecton the endothelial cells of the choriocapillaris after subretinaltransduction of the retinal pigment epithelium (RPE) with VEGF-A165vector. The choroidal endothelial cells were activated, adherentjunctions opened, and the fenestration was minimized, while theextracellular matrix localized between the RPE and the endothelium ofthe choriocapillaris was enlarged toward the lumen of the vessels,inducing a deep invagination of the endothelial cells into the vessellumen. They also proliferated and formed pathological vessels in thesubretinal space. Moreover,there was an increased expression of basicfibroblast growth factor and VEGF-A accompanied by macrophagestimulation, retinal edema, and photoreceptor loss. Conclusions: This is the first model ofVEGF-induced CNV in the rabbit in which the pathological eventsfollowing overexpression of VEGF by RPE cells have been described indetail. Many of the features of our experimental CNV resemble thoseobserved clinically in patients having wet age-related maculardegeneration.