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Damian Dorfman, Marcos Luis Aranda, María Florencia González Fleitas, Hernan H Dieguez, María Inés Keller Sarmiento, Ruth E Rosenstein; Visual input plays a key role in the retinal protection induced by enriched environment against acute retinal ischemia. Invest. Ophthalmol. Vis. Sci. 2016;57(12):96.
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© ARVO (1962-2015); The Authors (2016-present)
Enriched environment (EE) constitutes a strategy that boosts locomotor, exploratory, visual, and cognitive activities, as well as social interaction and voluntary physical exercise. Ischemia is a key component of several retinal diseases that are leading causes of irreversible blindness. We have shown that the exposure to EE protects the retina against acute unilateral ischemia in adult rats. In this work, we analysed the involvement of visual processing in the protection induced by EE against retinal ischemic damage.
Adult male Wistar rats were submitted to acute unilateral or bilateral ischemia by increasing intraocular pressure to 120 mm Hg for 40 min. After unilateral ischemia, animals were exposed to a standard environment (SE), a novelty environment (NE), or an EE for 3 weeks. NE consisted in standard laboratory cages, housing 2 animals and containing novelty objects that were weekly substituted, while EE consisted of big cages housing 6 animals, and containing food hoppers, wheels and different objects repositioned once/day and fully substituted once/week. Animals submitted to bilateral ischemia were exposed to SE or EE for 3 weeks. Retinal function (electroretinography, ERG), and histology were analysed at 3 weeks post-ischemia. Locomotor activity in EE was analysed in animals exposed to unilateral or bilateral ischemia. The expression of c-fos (immunofluorescence) in the retino-recipient layers of the superior colliculi (SC) was assessed in control animals, and animals submitted to unilateral or bilateral ischemia at 24 h of exposure to EE.
Unilateral ischemia induced a significant decrease in scotopic ERG a- and b- wave amplitude, and clear histopathological alterations. NE was ineffective in protecting the retinal function and structure against unilateral ischemia. EE, which preserved retinal function and histology against unilateral ischemia, did not protect the retina in animals exposed to bilateral ischemia, regardless that locomotor activity did not differ among groups. In animals submitted to unilateral ischemia, EE induced c-fos expression in the SC receiving projections from control and ischemic eyes. However, when ischemia was bilaterally induced, c-fos expression was absent in neither SC.
These results suggest that the protection induced by EE could involve visual processing information.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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