Intravitreal Rapamycin and Bevacizumab Inhibits VEGF Expression in a Swine Model of Neovascularization

Abstract

Purpose: : To assess if the association of intravitreal rapamycin and bevacizumab have an additive effect in decreasing vitreous VEGF levels more than bevacizumab alone. To assess the safety of intravitreal rapamycin in a porcine model of choroidal neovascularization.

Methods: : We included eight eyes in the study. A choroidal neovascularization was created using argon laser shots. We divided the eyes in four groups: Group A (N=2) was injected with 1ml of intravitreal bevacizumab alone (2.25 mg/ml). Group B was injected with balanced saline solution, group C with 0.5ml of rapamycin (1mg/ml) and bevacizumab and group D just with rapamycin. The eyes were enucleated 21 days after the injections. We performed RT-PCR studies to all samples.

Results: : A decrease in VEGF expression in group A, C and D was observed. The most important reduction was observed in group A. No structural damage was detected in eyes injected with intravitreal rapamycin or bevacizumab.

Conclusions: : Intravitreal rapamcin is safe for intravitreal administration with no structural alterations. The combination of rapamycin and bevacizumab is not better than bevacizumab alone in decreasing VEGF vitreous levels.

Keywords: retinal neovascularization • retina • neovascularization