Photothrombosis-induced ischemic neuronal degeneration in the rat retina.

Here we describe a new model for inducing ischemic neuronal degeneration in the adult rat retina. Rose bengal dye was injected intravenously; then the retina was exposed to intense light which caused vascular photothrombosis resulting in acute degeneration of retinal neurons. By either light or electron microscopical criteria, the acute neurodegernative reaction was judged identical in pattern, cytopathological appearance, and time course to the excitotoxic type of reaction typically seen in the retina following exposure to exogenous glutamate. These results reinforce other accumulating evidence suggesting that ischemic CNS damage is mediated by glutamate or related excitotoxins. The advantages of this model of CNS ischemia include its noninvasiveness, ease of application, authentic simulation of vascular thrombosis, and accessibility for application of neuroprotective drugs.