Sexually Dimorphic Effects of Prenatal Stress on Physical Growth and Stress-Related Behaviors in Prepubertal Mouse Offspring

Abstract

Several factors can modulate the link between fetal disruptions and later-life illnesses. The main objective of this thesis was to determine, in a mouse model, the impact of prenatal stressor timing and offspring sex on prepubertal metabolic and mental health outcomes. C57BL/6 dams in the first or second trimester of pregnancy experienced a restraint stressor or were left undisturbed. Pups were weighed daily until postnatal day (PND) 21, at which time fat distribution was measured. Anxiety- and depressive-like behaviors were tested on PND19-20 in open field, elevated plus maze, splash and tail suspension tests. Second trimester stressed males gained more weight and had increased fat deposits surrounding the kidneys. Although anxiety- and depressive-like behaviors were not apparent in prenatally stressed offspring of either sex, females stressed in utero exhibited a hyperactive phenotype. This work is the first to show sex- and trimester-specific consequences of early pregnancy stressors in prepubertal offspring.