A NOVEL MODEL OF CHOROIDAL NEOVASCULARIZATION IN RABBITS

Abstract

Purpose: To develop a new model of choroidal neovascularization (CNV) in rabbits that mimics consistent inflammation and leakage associated with age-related macular degeneration. This model can be a valuable tool to study disease development and may be used to evaluate new therapeutic options.

Methods: Twenty rabbits were randomly assigned into either experimental or control groups. Only the right eye of each rabbit was used for the study. In both groups, each rabbit eye received 12-16 Argon laser shots (power; 400mW, spot size; 75µm) which were aimed at Bruch’s membrane followed by intravitreal injection of 100µl of either vascular endothelial growth factor (VEGF; 100µg) for the experimental group or balanced salt solution for the control group. Injections were repeated after one week and fluorescein angiography (FA) and optical coherence tomography (OCT) were performed on a biweekly basis for an overall period of 8 weeks. The greatest linear dimension (GLD) of subretinal leakage was measured at the mid-to-late venous phase of the angiogram. Rabbits were euthanized at 8 weeks and eyes were processed for immunohistochemistry and electron microscopy.

Results: FA and OCT imaging showed persistent leakage in 90% of the laser-treated spots in the experimental group at the end of the 2-month study as compared with 5% activity in the control group. Statistical analysis of the data obtained from measurement of the GLD of leakage showed statistically significant differences between the 2 groups when comparing them at all time points. Moreover, intense vimentin and VEGF expression was noted in the experimental group compared with the control group confirming the intense fibrovascular nature of the developing CNV membranes.

Conclusions: Intravitreal VEGF injection augments a laser-induced CNV model in rabbits.

Keywords: 453 choroid: neovascularization • 412 age-related macular degeneration