Mapping early-life stress-induced behavioral adaptations in adolescent rats

Introduction/ Objectives: Adverse childhood experiences (ACEs) are deviations from standard conditions requiring significant psychological and neurobehavioral adaptations and can be modeled in rats through limited bedding and nesting (LBN) for postpartum dams. LBN disrupts maternal care, leading to behavioral adaptations in adult offspring. Additionally, adolescence is a critical period for social development; however, few studies exist examining this time point. In this study, we investigated the impact of LBN on social preference in adolescent rat males and females.

Methods: Female dams and their pups were exposed to either LBN conditions or normal bedding and nesting (naive) from postnatal day (PND) 2 to PND9. LBN conditions were normalized at PND10. Pups remained with their mothers until PND21, after which they were weaned and housed with same-sex littermates. At PND45, when rats reach adolescent age, social preference was assessed by measuring the amount of time an experimenter rat interacted with either a bystander rat or an inanimate object.

Results: Our findings reveal that adolescent females exposed to LBN exhibited a significant preference for inanimate objects oversocial interaction with an unfamiliar bystander. In contrast, no significant differences were observed in social interactions with a familiar bystander, regardless of sex or stress condition.

Conclusion: These results highlight sex-specific effects of early-life stress on social behavior and suggest adolescent females show preferential susceptibility to a disruption in social preference.