Abstract
Age-related decline in physical and cognitive functions are facts of life that do not affect everyone to the same extent. We had reported earlier that such cognitive decline is both sex- and context-dependent. Moreover, age-associated ultrastructural changes were observed in the hippocampus of male rats. In this study, we sought to determine potential differences in ultrastructural changes between male and female rats at various stages of life. We performed quantitative electron microscopic evaluation of hippocampal CA1 region, an area intimately involved in cognitive behavior, in both male and female adolescent, adult and old Wistar rats. Specifically, we measured the number of docking synaptic vesicles in axo-dendritic synapses, the length of active zone as well as the total number of synaptic vesicles. Distinct age- and sex-dependent effects were observed in several parameters. Thus, adult female rats had the lowest synaptic active zone compared to both adolescent and old female rats. Moreover, the same parameter was significantly lower in adult and old female rats compared to their male counterparts. On the other hand, old male rats had significantly lower number of total synaptic vesicles compared to both adolescent and adult male rats as well as compared to their female counterparts. Taken together, it may be suggested that age- and sex-dependent ultrastructural changes in the hippocampus may underlie at least some of the differences in cognitive functions among these groups.
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The datasets generated and analyzed during current study are available from the corresponding author on reasonable request.
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This work was supported by Shota Rustaveli National Science Foundation of Georgia. Grant number is DP2016_17. Author Mzia Zhvania has received this support.
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Data collection were performed by NP and NL electron microscopic imaging was performed by FR and EG statistical analysis of data was performed by NJ and YT The first draft of the manuscript was written by MZ, YT prepared the final version of manuscript. All authors reviewed the manuscript.
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Zhvania, M., Japaridze, N., Tizabi, Y. et al. Differential effects of aging on hippocampal ultrastructure in male vs. female rats. Biogerontology 24, 925–935 (2023). https://doi.org/10.1007/s10522-023-10052-z
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DOI: https://doi.org/10.1007/s10522-023-10052-z