CHARACTERIZATION OF COGNITIVE IMPAIRMENT IN TWO AGE GROUPS OF AGING RATS ON BARNES MAZE AND ITS MORFOLOGICAL CORRELATION IN DORSAL HIPPOCAMPUS

MOREL G; ANDRESEN T; HEREÑU C; ZUCCOLILLI G; GOYA G.R.

Huerta Grande Córdoba

Congreso; XXVIII Congreso de la Sociedad Argentina de Investigación en Neurociencias & Reunión Satélite: ?Bases Neurales de la Conducta: Neuroetología y Neurobiología de la Memoria en el Cono Sur?; 2013

Aging is the primary risk factor associated with the increment of neurodegenerative diseases. Human and animal studies have demonstrated age-related declines in learning and memory abilities. The hippocampus is a medial temporal lobe structure that is necessary for the formation of spatial memory. In previous studies, we observed a significant age-related reduction in dopaminergic neuron loss in hypothalamic nucleus and the substantia nigra in the Sprague?Dawley female rat (SD) which becomes more conspicuous at extreme ages. In the current work we extended the studies on our model of aging SD female rat, focusing on determining the extent of spatial memory impairment in two age group de senescent rats, 26 months old (OLD) and 29-32 months ( SENILE) and its histopatholical changes in dorsal hippocampus. A 4-6 months old control young rats was employed. Age changes in spatial memory performance were assessed on Barnes maze. The present study reveals differences between OLD and SENILE rats in acquisition and spatial memory retention. Morphological analysis of dorsal hippocampus shows a huge decrease (94-97 %) in DOUBLECORTIN neuron number in dentate gyrus in both senescent groups and a reduce (40%) in VIMENTIN glial number in hilus only in SENILE rats. We concluded that SENILE rats present a major degree of cognitive impairment than OLD rats on Barnes maze. Cognitive deficits in both senescent rats could be associated with a dramatic reduction in neurogenesis