Early ethanol exposure during gestation and lactation disrupts gut integrity and enhances ethanol intake in C57BL/6 mice offspring.

Prenatal alcohol (ethanol) exposure (PAE) produces enduring neurobehavioral alterations, but the contribution of gut integrity to this vulnerability remains unclear. This study examined if moderate-intermittent PAE, induced via voluntary ethanol intake during pregnancy and early lactation, alters colonic structure and barrier integrity-related markers in adolescent offspring, and whether these changes are associated with compulsive/perseverative behavior and increased ethanol intake. Pregnant C57BL/6 mice were exposed to a Drinking-in-the-Dark-based regimen or to water. In offspring, colonic tight junction-related gene expression (ZO-1, occludin, claudin), histological parameters (crypt length, lamina propria cell infiltration), immunofluorescence for junctional proteins, anxiety- and compulsive-like behavior, and voluntary ethanol intake were evaluated. Dams were later exposed to intragastric ethanol to evaluate intoxication sensitivity and subsequent voluntary drinking. PAE offspring showed a robust shortening of colonic crypts, and marked increased immune cell infiltration within the lamina propria, without significant changes in the levels of junctional proteins. PAE did not alter anxiety but increased marble burying and open field activity, enhanced object-directed perseveration (more object visits and shorter return latencies), and significantly elevated ethanol intake in adolescence. These effects were non-sex-specific. PAE induced minimal effects on ethanol sensitivity or intake in the dams. These findings indicate that PAE disrupts colonic integrity and immune status associated with compulsion-perseveration and heightened adolescent ethanol consumption, supporting a putative gut-brain-behavior pathway in PAE-related risk for alcohol use disorder.