Middle-aged rat hippocampus and some early changes accompanying aging

Abstract

Background: Studies of the middle-aged hippocampus may clarify the early mechanisms of aging and may lead to timely initiation of treatment for age-related cognitive impairments. Methodology: Young (2-m/o) and middle aged (15- and 17-m/o) rats were used with the aim to characterize early differences in electrophysiological properties, morphometrical changes and 1H-nuclear magnetic resonance (NMR) metabolite content in the hippocampus. Results: A decrease of the neuronal number accompanied by reduced width of the CA1 pyramidal cell layer was observed in middle-aged rats which may correspond to their reduced neurotransmission found in the CA3-CA1 synapse. An absolute value of mean magnitude of baseline field potential as well as of response obtained 51-60 min after high frequency stimulation was significantly lower in the middle-aged rats. The measurement of 1H-NMR metabolite content in hippocampal extracts of 2- and 17-m/o rats revealed that none of the sixteen metabolites identified can serve as a marker for middle-age-related changes. Conclusions: Functional and morphological changes are observed in middle-aged hippocampus. Therefore, 15-17-m/o rats could serve as proper animal model in studies focused on aging. Further studies aimed at timely prevention of early changes in the brain may contribute in slowing down of physiological brain aging. © 2012 Versita Warsaw and Springer-Verlag Wien.