Cognitive impairment and morphological changes in the dorsal hippocampus of very old female rats

MOREL GR; ANDERSEN T; PARDO J; ZUCCOLILLI GO; CAMBIAGGI V; HEREÑU CB; GOYA RG

NEUROSCIENCE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: New York; Año: 2015 vol. 303 p. 189 - 199

0306-4522

We have previously characterized the lactotrophic, reproductive and motor deficits of aging female rats. Here we assessed the extent of spatial memory impairment in old (26m) and senescent (29-32m) as compared to young (4-6m) female rats as well as the age-related histopathological changes in their dorsal hippocampus. Spatial memory performance was assessed with the Barnes maze. The results revealed that old rats perform better than senile rats in acquisition trials and young rats perform better than both aging groups. However, during ?short-term? (1 day) probe trials (PT) both aging groups showed a preserved spatial memory while in longer-term (5 days) PT, spatial memory showed deterioration in both aged groups. Morphological analysis showed a marked decrease (94-97%) in doublecortin neuron number in the dentate gyrus in both aged groups and a 40% reduction in vimentin-positive glial cell number in the hilus of aging rats. Astroglial process length and branching complexity decreased in aged rats. We conclude that while target-seeking activity and learning ability decrease in aged females, spatial memory only declines in the longer-term tests. The reduction in neuroblast number and astroglial arborescence complexity in the dorsal hippocampus are likely to play a role in the cognitive deficits of aging rats.