Social-defeat stress exposure during pregnancy induces abnormalities in spontaneous activity, sociality, and resilience to stress in offspring of mice.

BACKGROUND

Environmental stress during prenatal periods can lead to neurodevelopmental disorders. Psychosocial stress can be studied using the social-defeat stress (SDS) animal model. However, the effects of prenatal exposure to SDS on the behavior of mature offspring mice have not been clarified. The present study assessed the spontaneous activity and social interaction of pups born to mothers exposed to SDS during gestation, as well as their post-maturity responses to environmental stimuli, focusing on changes in anxiety-like behavior following restraint stress exposure.

METHODS

Pregnant C57BL/6 J mice were subjected to SDS for 4 days, from E12.5-E15.5, using aggressive male ICR mice. We assessed the mature offspring (after 10 weeks of age) born to these mothers for spontaneous activity, anxiety-like behavior, and social interactions, and evaluated their activity levels post-maturity following restraint stress exposure.

RESULTS

The open field test (OF) indicated reduced travel distance and duration in the SDS group versus controls, whereas home-cage monitoring showed increased area traveled. In a novel environment, the SDS group showed a decrease in interest in stranger mice. In a multiple-animal rearing environment, the SDS group showed an increase in the frequency and number of contact with other individuals. Movement duration in the OF following restraint stress reduced significantly from 30 min to 4 h in the control versus SDS group.

CONCLUSIONS

Prenatal exposure to SDS can result in behavior resembling developmental disorders, impacting spontaneous activity and social interactions. Altered responses to stress suggest potential brain function abnormalities in offspring after maturation due to maternal SDS exposure.