Chronic Intermittent Ethanol Vapor Exposure Paired with Two-Bottle Choice to Model Alcohol Use Disorder

Summary

Presented here is a protocol for the 2BC/CIE model of alcohol dependence in mice to study alcohol use disorder.

Abstract

Alcohol use disorder (AUD) is a chronic alcohol-related disorder that typically presents as uncontrolled drinking and preoccupation with alcohol. A key component of AUD research is using translationally relevant preclinical models. Over the past several decades, a variety of animal models have been used to study AUD. One prominent model of AUD is the chronic intermittent ethanol vapor exposure (CIE) model, which is a well-established approach for inducing alcohol dependence in rodents through repeated cycles of ethanol exposure via inhalation. To model AUD in mice, the CIE exposure is paired with a voluntary two-bottle choice (2BC) of alcohol drinking and water to measure the escalation of alcohol drinking. The 2BC/CIE procedure involves alternating weeks of 2BC drinking and CIE, which repeat until the escalation of alcohol drinking is achieved. In the present study, we outline the procedures for performing 2BC/CIE, including the daily use of the CIE vapor chamber, and provide an example of escalated alcohol drinking in C57BL/6J mice using this approach.

Introduction

Alcohol use disorder (AUD), which involves chronic excessive alcohol consumption, is one of the most common psychiatric disorders and is a global problem. AUD symptoms involve repeated cycles of intoxication, withdrawal, and cravings and are characterized by the constant consumption of alcohol without regard for the social, occupational, and health consequences^{1,2,3,4,5,6,7}. Alcohol use disorder often occurs in conjunction with other perv....

Protocol

All procedures were approved by the Purdue University Animal Care and Use Committee. The present study used 8 week old C57BL/6J mice. The CIE group had 5 mice (3 male, 2 female), and the Air group had 10 mice (5 male and 5 female). The animals were obtained from a commercial source (see Table of Materials) and were group-housed on a 12 h light-dark cycle with access to food. The body weights of the mice were measured once per week throughout the experiment.

1. General ex.......

Discussion

Alcohol use disorder represents a global public health problem with high prevalence and cost to society⁵². To study AUD in preclinical animal models, a common method in mice is 2BC/CIE^{20,34,39,40,47,53,54,55}. Here, this established m.......

Materials

Name	Company	Catalog Number	Comments
500 Eppendorf Tubes	Eppendorf	L203896J
95% ethanol	Decon laboratories	2816
Analox machine	Analox Instruments	Analox-AM1
Animal Weighing Scale	Kent Scientific	SCL-4000
Binder Clips	Office Depot	560394
C57BL/6J mice	The Jackson Laboratory	000664
Centrifuge	Eppendorf	5418R
Chronic intermitted vapor chamber	La Jolla Alcohol Research Inc		Custom made materials
Heparin/EDTA	Sagent Pharmaceuticals	TS/DRUGS/2/2015
Mouse bedding	Bed-o’Cobs	8B	fill with 1/8" deep
Mouse drinking bottle			Custom made materials
Pyrazole	Sigma-Aldrich	bccc6397
Teklad global 18% protein (mouse food)	Teklad global	Envigo 2018