Objectives: The details of the morphological features of choroidal neovascularization (CNV) remain unclear. The purpose of this study was to establish a CNV rat model and study the natural course of CNV using vascular casts and a scanning electron microscope (SEM).
Methods: Focal laser photocoagulation (argon green 50 mW, 0.04 s, 200 microm) was applied to Brown Norway pigmented rats. Choroidal vascular casts were prepared 1 and 3 days, 1 and 2 weeks, and 1, 3 and 6 months after laser photocoagulation. The choroidal casts were examined with a SEM.
Results: One day after photocoagulation, corrosion casts and SEM revealed complete defects of the choriocapillaris at the laser shot sites. One week after photocoagulation, small vascular buds originating from the damaged choriocapillaris were observed. Two weeks after photocoagulation, newly formed CNV originating from an individual laser burn was observed. One to three months after photocoagulation, these new vessels were connected to each other to form CNV networks. Six months later, some thin and atrophic vessels were observed in the CNV network.
Conclusions: We succeeded in making fine corrosion casts of CNV formed by photocoagulation in pigmented rats and in demonstrating the details of CNV formation and regression. It is hoped that the results of this study will contribute to the development of a drug therapy for CNV and to the interpretation of diagnostic imaging of CNV in humans.
Copyright 2002 S. Karger AG, Basel