Abstract
Purpose: :
The goal of this study is to assess the various lesions in an experimental VEGF/bFGF–induced rabbit model of choroidal neovascularization (CNV), which is characteristic of exudative aging–related macular degeneration (AMD).
Methods: :
Fluorescein angiographic (FA) images were captured from a TOPCON 50EX retinal camera with an IMAGEnet 200 program over a 10–minute time frame from adult male Dutch belted rabbits (N = 6) with experimental CNV, which was induced by suprachoroidal implantation of a non–biodegradable Hydron pellet to provide sustained release of both VEGF and bFGF. VEGF/bFGF–loaded pellets were implanted in the supra–choroidal space following methods previously described. The VEGF/bFGF Hydron pellets, which measure less than 1 mm in circumference (Wong et al., 2001), was further measured using the IMAGEnet 200 measurement tools. As negative controls, animals (N = 6) were implanted with blank Hydron pellets. The various CNV lesions were evaluated subjectively on size, type of leakage, and possible regression over 4 weeks and compared to size measurements utilizing the software measurement tools in IMAGEnet.
Results: :
The experimental CNV lesions developed reproducibly between 7 and 14 days after suprachoroidal VEGF/bFGF pellet implantation. Lesions were present up to 4 weeks with no signs of regression. The CNV lesion as computed by area and type of hyperfluorescence correlated with the location of the VEGF/bFGF pellet at the initial time points. Both the area of hyperfluorescence and changes in the area over time showed a linear decrease up to 8 weeks and at all time points correlated with intensity and subjective evaluation of the CNV lesions.
Conclusions: :
As in the clinical disease, CNV lesions associated with this non–laser rabbit model of AMD can occur as a function of both intensity and area of hyperfluorescence, or leakage. Both variables in this model also correlate with the CNV lesions and hence can be utilized to evaluate the quantitative response to experimental therapeutic treatment.
Keywords: choroid: neovascularization • age-related macular degeneration • growth factors/growth factor receptors