[Intraretinal neovascularization in rats with experimental renovascular hypertension]

Newly formed intraretinal vessels caused by experimental renovascular hypertension were studied histopathologically in rats. In these rats, dystrophy of the outer retinal layer and disappearance of retinal small capillaries were found in correlation with the duration of hypertensive state. In particular, retina obtained from rats with severe hypertension maintained for 6 months or more showed marked tissue damage and intraretinal proliferation of pigment epithelial cell with numerous microvessels. Most of these vessels were characterized by endothelial cell with large nuclei and slit-like narrowed lumina. Similar microvessels were also frequently observed in neighboring pigment epithelial cell layer. Endothelial fenestrations were observed in these vessels, although no findings were observed suggesting vessels penetrating through Bruch's membrane from the choroid. Similar vessels were also found in the inner plexiform layer and rarely in the nerve fiber layer. They were surrounded by processes resembling basal infolding of pigment epithelial cell. However, no fenestration of endothelial cells was found in these vessels.