[Histopathologic study of experimental chorioretinopathy induced in pigmented rabbits by intravenous adrenalin...

Experimental chorioretinopathy was induced by injecting 0.1% adrenalin intravenously in pigmented rabbit eyes. The fundus of each eye was analyzed with ophthalmoscopy and fluorescein fundus angiography (FFA). Histopathological sections were examined from each of following areas: (a) those with serous retinal detachment and evidence of dye leakage on FFA, (b) those with serous retinal detachment, but no dye leakage on FFA, and (c) those without detachment. In areas with serous detachment and dye leakage on FFA, the choroidal arterioles showed irregularly narrowed cavities, and the lumens of the choriocapillaris were remarkably narrowed. Most of the choroidal venules were enlarged and filled with many blood cells. Some had wide openings in the endothelial intercellular spaces, resulting in leakage of blood components into suprachoroidal space. Bruch's membrane was hypertrophic and some of overlying retinal pigment epithelium (RPE) had disappeared. The residual RPE showed degenerative changes, such as intracellular vacuole formation. Both in areas with detachment but no dye leakage on FFA, and in areas without detachment, similar but milder pathological changes were observed in choroidal arteriole and choriocapillaris. Severe damage, such as RPE defects and wide openings of endothelial intercellular spaces in choroidal venule, were not observed. These results suggest that intravenous adrenalin may affect choroidal venules as well as the choroidal arterioles and choriocapillaris in rabbit eyes, resulting in wide openings of their endothelial intercellular spaces. These histopathological change may lead to RPE damage by the choroidal ischemia and the leakage of blood components, leading to the induction of experimental chorioretinopathy.