Subretinal neovascularization in the rat induced by IRBP synthetic peptides

The present study was undertaken to develop a new animal model of subretinal neovascularization that does not involve traumatic manipulation of the eye. Using this model, the mechanism of subretinal neovascularization and its penetration through Bruch's membrane, and the various factors that contribute to this process were then examined. Male Lewis rats were immunized with interphotoreceptor retinoid binding protein (IRBP) peptide R-4, and the eyes histologically examined at various times up to 45 days after immunization. On day 12 after immunization, inflammatory cells were identified primarily in the anterior segment of the eye, with scattered cells in the retina and choroid. The inflammation was most prominent on day 14, by which time many eyes showed serous retinal detachment. By day 18 the inflammation had declined in intensity, but branches of the retinal vessels were seen extending into the choroid. Examination on day 30 revealed even fewer inflammatory cells but an accumulation of retinal pigment epithelial cells and mononuclear cells was present in the subretinal space. Examination on day 45 revealed no appreciable inflammation, but typical new vessels were found in the eyes from five of the 13 rats (38%) examined at that point. Mild inflammation of the retinochoroidal tissue can induce subretinal new vessels in rats, and this model will be useful for further study of subretinal new vessel formation.