Ethanol exposure during the brain growth spurt period increases ethanol‐induced aggressive behavior in adolescent male mice

Abstract

Ethanol exposure during development is associated with deficient social behavior, such as aggressive behavior, and ethanol consumption is associated with violent crimes, thus raising the possibility that individuals with fetal alcohol spectrum disorder may exhibit exacerbated social deficits in response to ethanol exposure. The present study evaluated the effects of ethanol exposure during the brain growth spurt period (i.e., a critical time period during which ethanol's effects are augmented) on aggressive behavior and ethanol-induced aggression during adolescence. From postnatal Day 2 (PD2) to PD8, Swiss mice received either ethanol (5g/kg, i.p.) or saline on alternate days. On PD39, aggressive behavior was assessed using the resident-intruder paradigm in male mice, and social dominance was investigated using the tube dominance test in both males and females. Testis structure and testosterone levels were evaluated in male mice. Early ethanol exposure increased the gonadosomatic index and the number of Leydig cells. The thickness of the seminiferous tube decreased. No difference in testosterone levels was found. The ethanol-exposed resident mice exhibited increased number and duration of aggressive episodes only when challenged with a low ethanol dose (1g/kg) before confrontation. Female mice early-exposed to ethanol won more confrontations in the tube dominance test. The present findings suggest a critical brain growth spurt period that is susceptible to ethanol-induced alterations of social dominance behavior in females. Although basal levels of aggression were unaffected, early ethanol exposure resulted in greater susceptibility to ethanol-induced aggression in adolescent male mice.