Dietary choline levels modify the effects of prenatal alcohol exposure in rats

Abstract

Prenatal alcohol exposure can cause a range of physical and behavioral alterations; however, the outcome among children exposed to alcohol during pregnancy varies widely. Some of this variation may be due to nutritional factors. Indeed, higher rates of fetal alcohol spectrum disorders (FASD) are observed in countries where malnutrition is prevalent. Epidemiological studies have shown that many pregnant women throughout the world may not be consuming adequate levels of choline, an essential nutrient critical for brain development, and a methyl donor. In this study, we examined the influence of dietary choline deficiency on the severity of fetal alcohol effects. Pregnant Sprague-Dawley rats were randomly assigned to receive diets containing 40, 70, or 100% recommended choline levels. A group from each diet condition was exposed to ethanol (6.0g/kg/day) from gestational day 5 to 20 via intubation. Pair-fed and ad lib lab chow control groups were also included. Physical and behavioral development was measured in the offspring. Prenatal alcohol exposure delayed motor development, and 40% choline altered performance on the cliff avoidance task, independent of one another. However, the combination of low choline and prenatal alcohol produced the most severe impairments in development. Subjects exposed to ethanol and fed the 40% choline diet exhibited delayed eye openings, significantly fewer successes in hindlimb coordination, and were significantly overactive compared to all other groups. These data suggest that suboptimal intake of a single nutrient can exacerbate some of ethanol's teratogenic effects, a finding with important implications for the prevention of FASD.

Keywords: Choline deficiency; Cliff avoidance; Fetal alcohol spectrum disorders; Hindlimb coordination; Open field activity; Prenatal ethanol.

Figure 1

Mean (+SEM) percent body weight gain during pregnancy. * = Lab chow (LC) dams gained significantly more weight compared to the pair-fed (PF) and ethanol (EtOH)-treated dams.

Figure 2

Mean (± SEM) body weights of offspring from postnatal day (PD) 1 to 10 (Panel A) and PD 11–21 (Panel B).

Figure 3

Mean (+ SEM) age that both eyes opened. Age of eye opening was significantly delayed among ethanol-exposed subjects also fed a diet with 40% choline levels. *** = significantly different from all other groups.

Figure 4

Percent of subjects that fell from the platform edge during a cliff avoidance task. Significantly more subjects from the 40% choline diet fell compared to subjects fed 70% or 100% choline diets.

Figure 5

Percent of subjects that were able to successfully retract from the platform edge in under 30 seconds. Despite falling, subjects fed the 40% choline diet were more successful at retracting from the platform compared to controls (Panel A). Similarly, subjects fed the 40% choline diet were significantly faster at retracting from the edge compared to subjects fed 70% or 100% choline diets (Panel B).

Figure 6

Grip strength and hindlimb coordination. Prenatal ethanol exposure significantly (*) delayed the age of the first successful grasp (Panel A) and first hindlimb coordination success (Panel B), when compared to LC and PF groups.

Figure 7

Grip strength and hindlimb coordination (either hanging for 30 seconds or getting the hindlimb to the rod). EtOH-exposed subjects fed 40% choline were significantly less successful than all groups except the EtOH+70 group. EtOH-exposed subjects fed 70% choline were less successful than all controls except the LC+70 group. ** = significantly different from all groups except EtOH+70; * = significantly different from all controls except EtOH+40 and LC+70 groups.

Figure 8

For the cumulative percentage of subjects successful for both trials/day, the severity of ethanol-related impairments in performance was affected by the severity of the choline deficiency.

Figure 9

Subjects exposed to prenatal alcohol and 40% choline diet took longer to habituate in the open field (A). Data from bins 3–8 are collapsed in Panel B. *** = significantly different from all other groups.