Environmental enrichment protects the retina from ischemic and diabetic damage in adult rats

Abstract

Environmental enrichment consists of a manipulation inwhich animals are exposed to complex conditions through adaptations in thephysical and social environment. This complex environment is composed bynesting materials, running wheels for voluntary exercise, tunnels, ladders, andtoys with different textures, colours, shapes, and sizes, which are changed ofplace to stimulate novelty, and provide continuous opportunity for explorationand stimulating sensory, cognitive, and physical activity. Exposure to enrichedenvironment induces changes in neuron morphology and synaptogenesis duringdevelopment, adulthood and aging. In addition to morphological changes, severalreports show that enriched environment housing provides a better recovery from difdifferent neuropathologies. In contrast, the adult retina has long beenconsidered less plastic than the brain cortex or hippocampus, the very sites ofexperience-dependent plasticity. In this chapter, we will discuss evidencesupporting that enriched environment protects the adult retina and optic nerveagainst damage induced by acute ischemia and type-1 diabetes. Although caremust be taken when extrapolating data obtained in experimental models tohumans, the protective effect of environmental enrichment could reflect ascenario in which a physically and mentally active lifestyle promotes thevisual pathway resiliency to disruption induced by ischemia and diabetes.