Intraocular Over Expression of Placental Growth Factor-1 (PlGF-1) Induces Corneal But No Choroidal Neovascularization

Abstract

Methods: : 1-2 months (rdy+-p) rats were used (6 eyes per conditions). Rat PlGF-1 was cloned in pVAX2 backbone plasmid. Injections of 10µl (30µg) of pVAX1-LacZ or pVAX2-PlGF-1 plasmids (driven by a CMV promoter) in PBS were performed either into the ciliary muscle or the subretinal spaces of rat eyes. Control eyes received ET of PBS. An iridium/platinum needle electrode was placed at the injection sites and a return plaque electrode was placed on the sclera. Electrical parameters were chosen to reach a 200V/cm field, with 8 pulses 20 ms duration (5Hz). Transfection was evaluated at one week using macroscopic examination for b-gal activity on histological sections. Clinical examination was performed at day 2, 8, 15, 30, 100 and semi-thin sections were performed at 30 and 100 days.

Results: : ET allowed for a safe an efficient transfection of ciliary muscle cells, or the retinal pigment epithelial cells (RPE) and for PlGF-1 secretion. At day 2, eyes that had received ET of PlGF-1 did not show any difference when compared control eyes. At day 8 and 30, when ET was performed in the ciliary muscle, intense central corneal neo vascularizations associated to vasodilatation was observed without any retinal neovascularization. When PlGF-1 was over expressed in RPE cells, no neovascularization was observed in the retina but on histology, sub retinal fluid accumulation along with retinal edema was observed.

Keywords: growth factors/growth factor receptors • gene transfer/gene therapy • neovascularization