EFFECTS OF SHORT-TERM HIGH-FAT DIET ON ASTROCYTIC REMODELING AND DCX<SUP>+</SUP> CELL MATURATION IN THE DORSAL HIPPOCAMPUS OF ADOLESCENT MICE

A balanced diet supports brain health, whereas high-energy foods can impair cognitive function, especially during critical periods like adolescence. Astrocytes play a key role in brain homeostasis and hippocampal neuroplasticity, but the impact of short-term high-fat diet (HFD) exposure during adolescence on this cell population is not well understood. In this study, we investigated if brief periods of HFD alter astrocyte morphology, density, and territorial volume. Specifically, we performed morphometric analysis of astrocytes following 1 or 2 weeks of HFD compared to Low-Fat Diet (LFD) in 4-week-old mice. We found that 1 w-HFD significantly increased astrocyte morphological complexity, territorial volume, and density compared with control group (1 w-LFD). Surprisingly, after 2 w-HFD, astrocyte complexity and territorial volume were decreased, while density remained unchanged compared with control mice. Since astrocytes have been involved in the regulation of postnatal hippocampal neurogenesis, in parallel we decided to evaluate morphological complexity and maturation of DCX⁺ cells under the same experimental conditions. Both 1 w- and 2 w-HFD negatively affected dendritic arborizations of DCX⁺ immature neurons, as well as the orientation and migration of DCX⁺ neuroblasts. These data suggest for the first time that short-term exposure to HFD exerts complex effects on astrocytes depending on its duration, while impairing maturation of DCX⁺ neuroblasts and immature neurons in the dorsal hippocampus of adolescent mice. Future studies will address functional consequences of such structural remodeling and the underlying mechanisms.
Funding: MIUR Progetti di Ricerca di Rilevante Interesse Nazionale (PRIN) Bando 2017—grant 2017XZ7A37