Establishment of the exudative age related macular degeneration model using the common marmoset

Abstract

Purpose: The purpose of this study was to establish an experimental exudative age related macular degeneration (AMD) model in the common marmoset (Callithrix jacchus), which is a small New World monkey.

Methods: Choroidal neovascularization (CNV) was induced by laser irradiation on the left eye of each animal under anesthesia. Eight laser spots were applied to around of macular area using the Image-Guided Laser System (532 nm) attached with Micon III at 650 - 2,000 mW power. Laser pulse duration and spot size were fixed at 100 ms and 50 µm, respectively. After 21 days of laser irradiation, fluorescein angiograms were observed. Then, they were transcardially perfused to the bilateral common carotid arteries with 4% paraformaldehyde for transverse section or with fluorescein-conjugated dextran (MW = 2,000 kDa) for retinal pigment epithelia (RPE)-choroidal flatmount. The eyeballs were removed after the perfusion, and then prepared coronal section of the retina for histology or RPE-choroidal flatmount for quantitative analysis of CNV lesion area.

Results: At 21 days after laser irradiation, late hyperfluorescence and leakage within or beyond the lesion borders were observed in a laser power-dependent manner. In histological analyses, CNV was observed in each laser-induced lesion, and their lesion areas were large depending on laser power. In RPE-choroidal flatmount, the mean size of the CNV lesions at 1,500 mW was 1.34 ± 0.49 × 105 µm² (Mean ± S.D., n = 29), and the coefficients of variation for each CNV area was 36.5% (n = 29).

Conclusions: We succeeded in producing an experimental wet-type of AMD model in the common marmoset, and this model may be useful in elucidating the pathophysiological mechanism and screening of new candidates for exudative AMD.

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