Affiliations: Department of Neurology, University of Greifswald,
Greifswald, Germany | Institute of Psychology, University of Greifswald,
Greifswald, Germany | Yerkes National Primate Research Center and Department
of Neurology, Emory University, Atlanta, Georgia, USA | University of Medicine and Pharmacy Craiova, Craiova,
Romania
Note: [] Corresponding author: Aurel Popa-Wagner, Ph.D., Department of
Neurology, University of Greifswald, Ellernholzstr. 1-2, 17487 Greifswald,
Germany. Fax: +49 3834 866843; E-mail: [email protected]
Abstract: Purpose: Aging is associated with a temporally dysregulated cellular
response to ischemia as well as poor functional recovery. While environmental
enrichment has been shown to improve the behavioral outcome of stroke in young
animals, the effect of an enriched environment on behavioral and
neuropathological recovery in aged animals is not known. Methods: Focal cerebral ischemia was produced by electrocoagulation of the right middle
cerebral artery in 3 month- and 20 month-old male Sprague-Dawley rats. The
functional outcome was assessed in neurobehavioral tests conducted over a
period of 28 days following surgery. Brain tissue was then immunostained for
proliferating astrocytes and the infarct and scar tissue volumes were measured. Results: Aged rats showed more severe behavioral impairments and
diminished functional recovery compared to young rats. Most infarcted animals
had disturbances of sensorimotor function, with recovery beginning later,
progressing more slowly, and reaching a lower functional endpoint in aged
animals. However, the enriched environment significantly improved the rate and
extent of recovery in aged animals. Correlation analysis revealed that the
beneficial effect of the enriched environment on recovery, both in young and
aged rats, correlated highly with a reduction in infarct size, in the number of
proliferating astrocytes, and in the volume of the glial scar. Conclusions: These results suggest that temporally modulating astrocytic
proliferation and the ensuing scar formation might be a fruitful approach to
improving functional recovery after stroke in aged rats.
Keywords: Aging, environment, ischemia, rat, recovery, scar, stroke
