Characterization of cognitive impairment in two age groups of aging rats on Barnes maze and its morphological correlation in dorsal hippocampus

MOREL GR; ANDERSEN T; HEREÑU CB; ZUCCOLILLI GO; GOYA RG

Huerta Grande, Córdoba

Congreso; XXVIII CONGRESO ANNUAL DE LA SOCIEDAD ARGENTINA DE NEUROCIENCIAS & Reunión satélite/ Neurobiología del compoertamiento y Neurobiología de la memoria en el cono sur; 2013

SAN

Aging is the primary risk factor associated with the increment of neurodegenerative diseases. The hippocampus, a medial temporal lobe structure necessary for the formation of spatial memory, is particularly affected during both normal and pathologic aging. Human and animal studies have demonstrated age-related declines in learning and memory abilities. In previous studies, we observed a significant age-related increase in dopaminergic neuron loss in the hypothalamus and the substantia nigra in the Sprague?Dawley female rat (SDfr) which becomes more conspicuous at extreme ages. In the present work we extended the studies in the SDfr, focusing on determining the extent of spatial memory impairment in 26 months (OLD) and 29-32 months old (SEN) as well as the histopatholical changes in their dorsal hippocampus, comparing them with their young counterparts (4-6 months old ). Age changes in spatial memory performance were assessed with the Barnes maze. The results revealed differences between OLD and SEN rats in acquisition and spatial memory retention. Morphological analysis of dorsal hippocampus showed a huge decrease (94-97 %) in DOUBLECORTIN neuron number in the dentate gyrus in both aging groups and a 40% reduction in VIMENTIN glial cell number in the hilus only in the SEN group. We conclude that SEN rats present a higher degree of cognitive impairment than OLD rats on the Barnes maze. Cognitive deficits in SDfr could be associated with a dramatic reduction in neurogenesis.