Environmental enrichment prevents behavioral deficits and oxidative stress caused by chronic cerebral hypoperfusion in the rat

Aims: The aim of the present study was to evaluate the neuroprotective effects of environmental enrichment (EE), assessed by cognitive activity in the Morris water maze, and on brain oxidative status, through measurement of macromolecules damage, lipid peroxidation levels, total cellular thiols and antioxidant enzymes in hippocampus, striatum and cerebral cortex. Main methods: Adult male Wistar rats were submitted to the modified permanent bilateral occlusion of the common carotid arteries (2VO) method, with right common carotid artery being first occluded, and tested three months after the ischemic event. Cognitive and physical stimulation, named Environmental Enrichment, consisted of one-hour sessions run 3 times per week during 12 weeks, following two different stimulation protocols: pre-ischemia and pre + post-ischemia. Rats were then tested for both reference and working spatial memory tasks in the water maze and later sacrificed for measurement of oxidative stress parameters. Key findings: A significant cognitive deficit was found in both spatial tasks after hypoperfusion; this effect was reversed in the 2VO enriched group. Moreover, hippocampal oxidative damage and antioxidant enzyme activity were decreased by environmental enrichment. Significance: These results suggest that both stimulation protocols exert a neuroprotective effect against the cognitive impairment and the reduction of biomarkers for oxidative damage caused by chronic cerebral hypoperfusion. (C) 2012 Elsevier Inc. All rights reserved.