Chronic psychological stress during adolescence induces altered postpartum behaviours and intergenerational effects in mice.

Abstract

Human studies of postpartum depression describe pre-pubertal adolescent stress as a predisposing factor of the condition, but varying degrees and types of stress that individuals may experience across childhood and adolescence make it difficult to describe the role of specific contributing factors. Animal models allow for standardization of experienced stress, but the effects of developmental stress and subsequent postpartum behaviours have not been well studied in rodent models. To address this gap in the literature, we subjected mice to chronic psychological stress in the early adolescent period using a chronic predator stress paradigm (aCPS). Control and aCPS mice were later bred to study the effects of aCPS on maternal postpartum behaviour. We found that aCPS dams provided less maternal care to their pups, groomed less frequently in the sucrose splash test, and consumed less of a high effort food source (unshelled sunflower seeds) in a food foraging test after giving birth compared to controls. The offspring of aCPS mice (ancestral aCPS) show some increased anxiety-like behaviours as adults, suggesting an intergenerational effect. Our findings suggest that early adolescent predator stress impacts aspects of motivation in the postpartum period and has intergenerational effects that persist into adulthood in both males and females.