A Mouse Model of Prenatal Vitamin D Deficiency: Effects on Offspring Behavior, Systemic Immune and Gut Microflora Profiles

Background: Vitamin D deficiency/insufficiency, defined as inadequate circulating concentrations of 25-hydroxyvitamn D (25OHD), has been estimated to affect up to 75% of pregnant women in some developed nations. Multiple studies have established an associative link between low maternal 25OHD concentrations and a variety of mental health conditions, including autism spectrum disorders (ASD).

Objectives: The current study aimed to examine the effects of prenatal vitamin D deficiency on offspring behaviors. Additionally, as immune and gastrointestinal dysregulation is seen in some individuals with autism, we examined the effect of prenatal vitamin D deficiency on immune and gut microflora profiles in offspring.

Methods: Female C57BL/6J mice were assigned to either a vitamin D deficient diet or a control diet two weeks prior to mating and maintained on this diet throughout pregnancy until postnatal day 7, at which point both dietary groups were switched to the control diet. We subsequently recorded the ultrasonic vocalizations of the offspring on postnatal day 8 as a measure of social communication. Beginning on postnatal day 60, the adult offspring were tested for levels of social interaction using the Crawley 3-chamber social approach task. Anxiety was tested using the elevated-plus maze, and general activity levels were assessed using the open field. Offspring were euthanized after the completion of behavioral testing, at which time serum, white adipose tissue, liver, intestines, and quadricep were collected from all male offspring. Offspring serum was tested for eight immune analytes to examine if prenatal vitamin D status had long lasting effects on general systemic inflammation. Adult offspring intestinal microbiota was analyzed for microflora profiles, examining a variety of different microfloral species.

Results: There were no differences in behavior between offspring prenatally exposed to the vitamin D deficient diet and control offspring. Out of eight immune analytes measured, the vitamin D deficient offspring had significantly higher levels of the proinflammatory markers resistin and IL-2 than control offspring. Further, vitamin D deficient offspring were found to have a significantly altered gut microflora profile than that of control offspring.

Conclusions: These results suggest that despite emerging theories, it does not appear that prenatal vitamin D deficiency leads to the development of autistic-like behaviors in offspring, However, is important to note that prenatal vitamin D deficiency may lead to abnormalities in behaviors not tested in the current study. Despite no changes in behavioral profiles between groups, prenatal vitamin D deficiency does appear to have long lasting consequences on systemic immune and gut microflora profiles in adult offspring. Further research is needed to determine whether prenatal deficiency leads to other cognitive and behavioral deficits in offspring as well as any other long-lasting physiological differences.