Maternal allergic inflammation in rats impacts the offspring perinatal neuroimmune milieu and the development of social play, locomotor behavior, and cognitive flexibility.

Maternal systemic inflammation increases risk for neurodevelopmental disorders like autism, ADHD, and schizophrenia in offspring. Notably, these disorders are male-biased. Studies have implicated immune system dysfunction in the etiology of these disorders, and rodent models of maternal immune activation provide useful tools to examine mechanisms of sex-dependent effects on brain development, immunity, and behavior. Here, we employed an allergen-induced model of maternal inflammation in rats to characterize levels of mast cells and microglia in the perinatal period in male and female offspring, as well as social, emotional, and cognitive behaviors throughout the lifespan. Adult female rats were sensitized to ovalbumin (OVA), bred, and challenged intranasally on gestational day 15 of pregnancy with OVA or saline. Allergic inflammation upregulated microglia in the fetal brain, increased mast cell number in the hippocampus on the day of birth, and conferred region-, time- and sex- specific changes in microglia measures. Additionally, offspring of OVA-exposed mothers subsequently exhibited abnormal social behavior, hyperlocomotion, and reduced cognitive flexibility. These data demonstrate the long-term effects of maternal allergic challenge on offspring development and provide a basis for understanding neurodevelopmental disorders linked to maternal systemic inflammation in humans.