In a Preclinical Model of Prenatal Alcohol Exposure, an Iron Supplementation Intervention Reduces Anxiety-Like Behavior in Both Sexes and Improves Growth in Males

Abstract

Objectives Both prenatal iron deficiency and prenatal alcohol exposure (PAE) decrease body weight, increase susceptibility to anxiety, and impair memory and learning in the offspring. PAE itself causes fetal iron deficiency, even when mothers consume sufficient iron. We hypothesized that iron supplementation in PAE pregnancies would not alter offspring growth but would improve measures of anxiety, learning, and memory. Methods Pregnant Long-Evans rats received 5 g/kg/day ethanol or isocaloric maltodextrin (split-dose) from gestational day (GD) 13.5–19.5 and received 6 mg/kg/day iron as ferric sulfate or water from GD12.5–19.5. Male and female offspring were weighed regularly after birth and underwent elevated plus maze (postnatal day (P) 27), open field (P28), novel object recognition (P29–30), T-maze (P32–40), and fear conditioning (P42–50) tests. Mixed model analysis was used to determine significance of the effects of PAE, iron, and sex. Results PAE reduced postnatal body growth in both male (P = 0.028) and female (P = 0.026) offspring. In both sexes, PAE interacted with age to affect growth (P < 0.001) from P5 to P50. In males but not females, iron supplementation interacted with age (P = 0.044) and age and PAE (P = 0.045) to improve growth in PAE + iron males, such that their weights approached control weights by P50. On the elevated plus maze, iron supplementation, regardless of PAE or sex, increased time spent on the open arms by 39–118%, indicating reduced anxiety-like behavior (P = 0.030). On the open field test, time spent in the center was not affected by PAE, iron, or sex (P’s > 0.200). On the novel object recognition test, at delays of both 1 and 24 hours, all groups (except MD + Iron Males with 24-hour delay) recognized the novel object better than chance (P’s < 0.040), but recognition at both time delays was not affected by PAE, iron, or sex (P’s > 0.120), showing that these did not affect recognition memory. On the T-maze and fear conditioning tests, which assess learning and memory, PAE, iron, and sex had no effect on the results (P’s > 0.080). Conclusions This work is the first to investigate gestational iron supplementation as an intervention for alcohol-exposed pregnancies. These results suggest iron supplementation may improve outcomes such as growth in males and anxiety in both sexes in alcohol-exposed populations. Funding Sources NIAAA NIDDK.