Role of gut microbiota and its functional products in prenatal alcohol-induced anxiety-like behavior. KW1

Prenatal alcohol exposure (PAE) has been shown to increase vulnerability to anxiety. Alterations in the gut microbiota and its functional output (i.e., short-chain fatty acids, SCFAs) are a potential mechanism underlying anxiety behaviors induced by PAE. This study uses a well-established rat model of PAE to examine the impact of alcohol consumption during gestation on anxiety-like behaviors, the gut microbiota, and SCFA levels in adult male and female offspring. PAE male and female rats exhibited increased anxiety-like behavior on the open field test; moreover, control animals displayed striking sex differences in the light-dark test, but sex differences were attenuated among PAE males and females. PAE did not affect bacterial diversity and community structure in adulthood; however, in males, PAE increased the abundance of the Bacteroidetes phylum, reduced the abundance of the Firmicutes phylum, and decreased the abundance of the Lachnospiraceae NK4A136 group genus compared to controls. In females, PAE increased abundance of Anaerotruncus and Turicibacter genus compared to controls. PAE did not affect fecal SCFA concentrations but SCFAs were positively associated with anxiety-like behaviors in control, but not PAE males. There were no significant associations between anxiety-like behavior and bacterial taxa that were altered by PAE. This study highlights several bacterial taxa potentially involved in the mechanisms through which PAE induces anxiety-like behaviors. These findings also underscore the importance of considering sex differences when assessing anxiety-like behavior and gut microbiota to identify potential biomarkers for interventions targeting mental health issues in individuals with PAE.