Age-related morphological changes in the hippocampus in two mouse strains

The granule cell number (nGR) in the dentate gyrus (DG) has been reported to vary considerably among inbred strains of mice, thus providing proof of some genetically associated components to this variation. Furthermore, several authors have described age-related morphological changes in the DG in both humans and animals, but there is no general agreement in the literature about the occurrence of such changes. The purpose of this study was to investigate for strain differences in hippocampal structure changes in old C57BL/6J (B) and DBA/2J (D) mice as compared with younger ones. The nGR in the DG, as well as other structural parameters of the hippocampus, were determined in female B and D mice of 4 and 24 months. The two-way analysis of variance indicated a significant interaction between 'strain' and 'age' for the nGR, suggesting that this parameter changes differently with age in B and D mice. This finding indicates that these strains could present a differential susceptibility in granule cell aging raising the possibility that age effects on the granule cell population in the DG could be influenced by some hereditary factors.