Maternal stress prior to conception impairs memory and decreases right dorsal hippocampal volume and basilar spine density in the prefrontal cortex of adult male offspring

Abstract

Chronic parental stress impacts offspring functioning throughout life. Chronic variable stress prior to conception impairs offspring development in terms of behavior, neuroanatomy, and neurobiology. Previously, our lab demonstrated that even a consistent stressor experienced by the sire or the dam shapes offspring development beginning in early life. Here, we show how consistent maternal stress prior to conception influences the brain and behavior of offspring in adolescence and adulthood. Female Long-Evans rats were exposed to elevated platform stress twice daily for 27 consecutive days immediately prior to mating with non-stressed males. Male and female offspring were assessed in the open field and elevated plus maze in adolescence, and open field, elevated plus maze, Whishaw tray reaching, and Morris water task in adulthood. Offspring were then euthanized, and their brains were stained with Golgi-Cox solution and then examined for dendritic spine density and hippocampal volume. Major findings include deficits in spatial memory, decreased medial prefrontal cortex spine density, and reduced right dorsal hippocampal volume in male offspring only. This work illustrates that the effects of consistent maternal stress prior to conception are lifelong and highly sexually dimorphic.

Keywords: Pregestational stress; hippocampus; prefrontal cortex; sex differences; spatial memory; spine density.