PURPOSE: The authors document an animal model of retinal pigment epithelial (RPE) detachments. METHODS: N-ethylmaleimide (NEM) and sodium iodate (sulfhydryl-alkylating agents) were injected into the vitreous of Dutch pigmented rabbits. Subretinal fluid samples were withdrawn 0.5 and 3 hours after NEM injections and analyzed for albumin content by gel electrophoresis. Selected eyes were examined histologically. RESULTS: Injections of 9.2 micrograms NEM caused wrinkling of the retina within 15 minutes, at which time fluorescein angiography revealed multifocal RPE detachments. At this stage, histologic sections showed moderate choroidal edema and RPE detachment. Elevated retinal detachments developed over the next 15 to 25 minutes. Histologic sections showed massive choroidal edema and RPE fragmentation. The albumin concentration of subretinal fluid rose from 60% of serum level at 30 minutes after NEM to 80% after 3 hours. Sodium iodate did not cause choroidal edema or RPE detachment. CONCLUSION: In rabbits, intravitreal NEM causes the rapid appearance of choroidal edema and RPE detachment, followed by serous retinal detachment. The initial effect probably is caused by an alteration of choroidal vascular permeability. The relationship of these effects to sulfhydryl alkylation is unclear because sodium iodate failed to produce RPE detachments. N-ethylmaleimide effects may model aspects of clinical RPE and serous retinal detachments.
PURPOSE: The authors document an animal model of retinal pigment epithelial (RPE) detachments. METHODS:N-ethylmaleimide (NEM) and sodium iodate (sulfhydryl-alkylating agents) were injected into the vitreous of Dutch pigmented rabbits. Subretinal fluid samples were withdrawn 0.5 and 3 hours after NEM injections and analyzed for albumin content by gel electrophoresis. Selected eyes were examined histologically. RESULTS: Injections of 9.2 micrograms NEM caused wrinkling of the retina within 15 minutes, at which time fluorescein angiography revealed multifocal RPE detachments. At this stage, histologic sections showed moderate choroidal edema and RPE detachment. Elevated retinal detachments developed over the next 15 to 25 minutes. Histologic sections showed massive choroidal edema and RPE fragmentation. The albumin concentration of subretinal fluid rose from 60% of serum level at 30 minutes after NEM to 80% after 3 hours. Sodium iodate did not cause choroidal edema or RPE detachment. CONCLUSION: In rabbits, intravitreal NEM causes the rapid appearance of choroidal edema and RPE detachment, followed by serous retinal detachment. The initial effect probably is caused by an alteration of choroidal vascular permeability. The relationship of these effects to sulfhydryl alkylation is unclear because sodium iodate failed to produce RPE detachments. N-ethylmaleimide effects may model aspects of clinical RPE and serous retinal detachments.