Sex differences in binge alcohol drinking and the behavioral consequences of protracted abstinence in C57BL/6J mice

Abstract

BackgroundBinge alcohol drinking is a risk factor linked to numerous disease states including alcohol use disorder (AUD). While men binge drink more alcohol than women, this demographic gap is quickly shrinking, and preclinical studies demonstrate that females consistently consume more alcohol than males. Further, women are at increased risk for the co-expression of AUD with neuropsychiatric diseases such as anxiety and mood disorders. However, little is understood about chronic voluntary alcohol drinking and its long-term effects on behavior in females. Here, we sought to characterize sex differences in chronic binge drinking and the effects of protracted alcohol withdrawal on anxiety- and affective-related behaviors in males and females.MethodsWe assessed binge alcohol drinking patterns in male and female C57BL/6J mice using a modified Drinking in the Dark (DID) paradigm in which mice received home cage access to one bottle of 10% or 20% alcohol (EtOH) or water for 2 hrs per day on Days 1-3 and to two bottles (EtOH/H2O + H2O) for 24 hrs on Day 4 for eight weekly cycles. Mice were then tested for the effects of protracted abstinence on avoidance, affective, and compulsive behaviors.ResultsFemale mice consistently consumed more alcohol than males, with a more robust sex difference for 20% than 10% EtOH. Higher alcohol intake in females was biased toward the early access period (2-4 hrs) but was not dependent on higher overall water/fluid intake. Alcohol preference was higher in 10% vs. 20% EtOH but there was no difference between sexes. Protracted alcohol abstinence decreased avoidance behavior (elevated plus maze, open field, novelty suppressed feeding) and increased compulsive behavior (marble burying) in females but not males, and there was no effect of alcohol history on stress coping and negative affective behaviors (sucrose preference, forced swim test, tail suspension) in either sex.ConclusionFemale mice engaged in higher volume binge drinking than their male counterparts; further, protracted abstinence from chronic binge drinking resulted in a female-specific behavioral disinhibition that may be related to greater alcohol intake. These results have implications for sex-dependent alcohol drinking patterns and long-term negative neuropsychiatric/physiological health outcomes in humans.HighlightsFemale mice consistently consumed more alcohol than males, with a more robust sex difference in consuming high (20%) versus lower (10%) concentration alcohol.Female alcohol intake was biased towards the first 2-hrs of each drinking session. While females consumed more water than males at the 24-hr timepoint, there was no difference in the first 2-hrs of drinking sessions suggesting elevated female alcohol intake is not driven by increased liquid consumption.Alcohol preference was elevated for 10% versus 20% alcohol but there was no difference between the sexes.Protracted alcohol abstinence decreased avoidance behavior and increased impulsivity in females only, with no effect in males.There was no effect of protracted alcohol abstinence on anhedonia in either sex.SummaryThe overconsumption of alcohol is a widespread public health issue linked to numerous diseases and mental health issues including anxiety among others. Binge drinking, defined as having 4-5 drinks in a 2-hour period, is more common in men than women but that demographic gap is shrinking. Mice are commonly used as an animal model of alcohol consumption and binge drinking to study behaviors associated with/resulting from alcohol drinking. We found that female mice consume more alcohol compared to their male counterparts, and furthermore, that following long-term alcohol consumption and abstinence, females but not males displayed reduced anxiety and increased compulsive behavior. Although high levels of anxiety that remained sustained for long periods of time are considered to negatively affect mental/physical health, some amount of anxiety is healthy to reduce behaviors that may compromise well-being including potentially binge drinking. We propose that this behavioral outcome may denote increased risk-taking behavior and that the reduction of anxiety in females may lead to negative outcomes.