LASTING DISRUPTION OF AFFECTIVE BEHAVIOUR AND DENTATE GYRUS CIRCUITRY IN FEMALE OFFSPRING EXPOSED TO A MATERNAL PLANT-BASED HIGH-FAT DIET

Maternal nutrition plays a critical role in shaping long-term neurobehavioral outcomes in offspring. Exposure to a maternal high-fat diet (mHFD) has been associated with an increased risk of depression-related disorders, with marked sex-specific vulnerability. As modern dietary patterns increasingly incorporate plant-based fats instead of animal-derived fats, plant-based high-fat diets have become an important but underexplored model for studying obesity and its effects on developmental programming. This study aimed to investigate whether maternal exposure to a plant-based mHFD induces depression-like behaviour and hippocampal alterations in adult female offspring. Adult female Wistar rats were fed either a mHFD or a control diet (CD) prior to mating, and throughout gestation and lactation. Females were weaned on a CD, forming two groups: offspring from CD dams (FC) and offspring from mHFD dams (FH). In adulthood, depression-like behaviour was assessed using the sucrose preference test (SPT) to evaluate anhedonia and the forced swimming test (FST) to assess helplessness, with behavioural testing performed during the diestrus phase. Hippocampal alterations were examined by quantifying parvalbumin-positive (PV) interneurons and GFAP-positive astrocytes across hippocampal subregions. FH animals exhibited reduced sucrose preference and lower fluid consumption (p<0.05), as well as increased immobility time (p<0.05). Immunohistochemical analysis revealed a significant reduction in PV+ interneurons and GFAP+ astrocytes in the dentate gyrus (p<0.05), with no differences observed in CA1 or CA2/3 subregions. These findings demonstrate that long-lasting maternal exposure to a plant-based high-fat diet induces a persistent depression-like behaviour in adult female offspring, accompanied by region-specific disruption of hippocampal microcircuitry.