Do prenatal immune activation and maternal iron deficiency interact to affect neurodevelopment and early behavior in rat offspring?

Infection and iron deficiency are common during pregnancy and studies have described altered brain development in the offspring as a result of these individual maternal exposures. Both exposures have been identified as risk factors for schizophrenia yet they have never been modeled simultaneously. We developed a rat model of prenatal immune activation on a background of maternal iron deficiency to determine whether these factors interact to affect neurodevelopment and early behavior in offspring. Pregnant rats were placed on iron sufficient (IS) or iron deficient (ID) diets from E2 to P7, and administered LPS or saline on E15/16. Iron was reduced in liver, spleen, serum and placenta from ID dams by E15. LPS administration on E15 caused greater induction of serum interleukin-6 and tumor necrosis factor-α in ID dams compared to IS dams. Offspring (P0, P7) from ID dams had reduced iron in spleen, liver and brain compared to IS, which normalized by P21. Pups from ID dams showed differences in forelimb grasp and acoustic startle, whilst pups from LPS dams displayed differences in grip ability, geotaxis reflex, cliff avoidance and acoustic startle. Offspring from LPS dams displayed reduced locomotor activity at P7 and P60; offspring from ID dams showed no change. Our findings show effects of prenatal LPS and maternal iron deficiency were additive, such that offspring exposed to both insults displayed more neurodevelopmental abnormalities than offspring exposed to one alone. Yet surprisingly there was no interaction between factors, suggesting independent mechanisms of action.