Table 1.

Animal models of alcohol abuse

Model	Species	Application
Gavage (I/G)
Animals are allowed free access to rodent chow and water. Alcohol or the vehicle is delivered orally into the stomach either via curved blunted tipped feeding needle attached to a syringe or a pediatric feeding tube [Plackett and Kovacs 2008; Majchrowicz 1975].	Rodents and rabbits	The model has been used extensively to study adverse effects of acute and chronic alcohol abuse alone (First Hit) and in association with other insults (“Second Hit” e.g. burn injury, bacterial challenge, viruses, hemorrhagic shock and smoking) on various organs and systems including the liver [McCuskey et al., 2005; Ito et al., 2004; Gong et al., 2008; Carmiel-Haggai et al., 2003; Wheeler and Thurman 2003; Bautista and Wang 2002], brain [Tiwari et al., 2009], blood [Pruett et al., 2004; Schwab et al., 2005], esophagus[Bor et al., 1998; Bor and Capanoglu 2009], myocardium [Kannan et al, 2004], skeletal muscle [Frost et al., 2005], lung [Zhang et al., 2007], gut [Kavanaugh et al., 2005; Choudhry and Chaudry, 2008; Li et al., 2009; Keshavarzian et al., 2009], immune system [Pruett et al., 2004; Bautista and Wang 2002], pancreas [Letko et al., 1991] and on fetus development [Maier et al., 1996; Gibson et al., 2000]. The model has also been used to study alcohol dependence and alcohol-induced epigenetic changes in a variety of organs [Faingold 2008; Kelly and Lawrence 2008; Kim and Shukla, 2006).
Intravenous (IV) infusion
Animals have free access to rodent chow and water. Alcohol or the vehicle is administered IV as a bolus injection followed by a continuous infusion via a catheter implanted in jugular, femoral or cephalic vein [D’Souza et al., 1989; Zink et al., 2001; Gillmian 1989; Wilkinson and Rheingold, 1981].	Rodents, pigs, dogs, and sheep	The model has been used to study hypothermic, tolerance [Gilliam 1989], metabolic [Molina et al., 1989, 1991; D’Souza et al., 1991,1992] hemodynamic [Zink et al., 2001; Molina et al., 2004], immunological [Bautista et al., 1991; Bautista 2002], and neuroendocrine [Molina et al., 2004] changes induced by acute alcohol intoxication alone and in association with a Second Hit in numerous organs including liver [Bautista 2002; Spitzer and Zhang 1996], muscle [Pagala et al., 1995; Vary and Lang 2008], blood [Spitzer and Zhang 1996], brain [Pawlosky et al., 2010], and the lung [Spitzer et al., 2002].
Intraperitoneal (IP) injection
Animals have free access to rodent chow and water. Alcohol or the vehicle is administered as an IP injection [D’Souza et al., 2007].	Rodents and guinea pigs	The model has been used extensively, alone and in association with a Second Hit, to study the adverse effects of acute alcohol intoxication on a variety of organs including lung [D’Souza et al., 2007; Bagby et al., 1998; Kolls et al., 1998; Walker et al., 2008; Lanzke et al., 2007; Happel et al., 2006], liver [Blanco et al., 2005; Emanuele et al., 2007], muscle [Paice et al., 2002; Lang et al., 2004; Vary and Lang, 2008; Salem et al., 2002], male reproductive axis [Emanuele et al., 2008], the cardiovascular system [McDonough et al., 2002], brain [Zhao et al., 1997; Guaza et al., 1983], the immune system [Bird and Kovacs, 2008; Emanuele et al., 2009], and on developing fetus [Da Lee et al., 2004] and the fetal lung [Wang et al., 2007]. In addition, the model has also been used to show that a single episode or binge drinking may augment the transition of pancreatic edema to acute pancreatitis [Letko et al., 1991].
Alcohol in liquid diet (Oral)
A. Lieber DeCarli liquid diet The animals have free access to alcohol in Lieber DeCarli liquid diet. The model involves pair-feeding of control animals isocaloric diet [Lieber and DeCarli 1982].	Rodents and non human primates (baboons and rhesus macaques)	Variation A of the liquid diet model has been used widely, alone and in association with another insult, to study biochemical, physiological, morphological, immunological and pathological consequences of chronic alcohol abuse on numerous organs. These include the liver [Lieber et al., 1989; Earnest et al., 1993; Bhopale et al., 2006; Deaciuc et al., 2001], pancreas [Perides et al., 2005; Kubisch et al., 2006; Vonlaufen et al., 2007a; Gukovsky et al., 2008], gastrointestinal tract [Fleming et al., 2001], lung [Mason et al., 2004; Brown et al., 2001; Vander Top et al., 2005; Brown et al., 2007], bone [Sampson et al., 1996], muscle [Kim et al., 2001], brain [Herrera et al., 2003] as well as the immune [Jerrells et al., 1990; Worrall and Wilce, 1994] and neuroendocrine [Emanuele et al., 2005] systems. The model has also been used in identifying mechanisms involved in pathogenesis of alcoholic diseases [Roychowdhury et al., 2009; Hritz et al., 2008], in the development of tolerance and physical dependency on alcohol, fetal alcohol syndrome [Parnell et al., 2006], and in identifying novel markers of alcoholic disease [Bradford et al., 2008].
B. Fish oil rich liquid diet formulation The animals have free access to alcohol in a liquid diet formulation rich in fish oil. The model involves pair-feeding of control animals isocaloric diet [Tipoe et al., 2008].	Rodents	Variation B of the liquid diet model is reported to produce some of the pathological changes not observed with the Lieber-DeCarli liquid diet and also reproduce all pathological changes observed with the intragastric ethanol infusion model [Tipoe et al., 2008].
C. Sustacal or Carnation Slender liquid diet These are commercially available flavored and sweetened liquid diets to which alcohol is added. Animals in the alcohol group are allowed free access to the alcohol containing diet while those in the control group are pair-fed isocaloric diet [de Fiebre et al., 1994].	Rodents	Variation C of the liquid diet model has been used to study the effects of chronic alcohol abuse on developing brain (prenatal exposure) [Zhou et al., 2001], the hypothalamic-pituitary-thyroid axis [Zoeller et al., 1996], and the immune system [Bautista 1995].
Tsukamoto- French (IEI) Model (Enteral)
The diet of desired composition is prepared in the liquid form with or without alcohol and administered continuously into the stomach via a permanent gastric cannula (enteral). The control animals are pair-fed isocaloric diet [Tsukamoto et al., 2008].	Rodents, guinea pigs, and non human primates	The model in association with a second hit [Tsukamoto et al., 2009] has been used primarily to elucidate mechanisms involved in the development and progression of alcoholic liver disease [Tsukamoto 1998; Wheeler et al., 2003; Hines and Wheeler, 2004; Uesugi et al., 2001, 2002; Deaciuc et al., 2004; Baumgardner et al., 2007; Oliva et al., 2009]. The model has also been used in studies such as those designed to study ethanol-induced bone loss during pregnancy, to explore the implications of nutrition ethanol interaction during gestation on the fetus [Shankar et al., 2006a, 2006b}, and to study the effects of chronic alcohol abuse on immunity [Siggins et al., 2009]. The enteral protocol of this model has been used to develop a rodent model of chronic alcohol-induced pancreatitis and also an intragastric model suited for use in genetically manipulated mice [Kono et al., 2000 and 2001].
Alcohol in drinking water
A. Single bottle-no choice The animals have unrestricted access to rodent chow and either water or alcohol in drinking water [Coleman et al., 2008].	Rodents and non-human primates	Variation A of the model is used in association with a Second Hit to explore the mechanisms by which chronic alcohol abuse induces metabolic [Seiva et al., 2009; Kudo et al., 2009; Macho et al., 2003], morphological [Evrard et al., 2006; Andersson et al., 1995; Sarphie et al., 1996], immunological, and functional [Cook et al., 2004; Zhu et al., 2004; Song et al., 2002; Abdallah et al., 1988; Blank et al., 1991; Meyerholz et al., 2008; Edsen-Moore et al., 2008] changes in organs and cells and increases susceptibility to infections [Jerrells et al., 2007], [Masui et al., 2002]. The model has also been used to study effects of (uterine) chronic alcohol abuse on fetal lung development [Gauthier et al., 2005], on bone mineral content [Broulik et al., 2009], and in the exercebation of liver damage induced by other hepatotic agents [Nadkarni and D’Souza 1988; Nadkarni et al., 1983].
B. Two bottle- free choice The animals have free access to rodent chow and an unrestricted choice between water and alcohol [Rhodes et al., 2005; Ehringer et al., 2009].	Rodents and rhesus macaques	Variations B C and D are very valuable for studies designed to explore neurochemical and molecular pathways that contribute to alcohol abuse. These variations have also been used in studies such as ones designed to identify the genetic basis for alcohol preference and dependence [Samson et al., 1998; Rhodes et al., 2007; Yoneyama et al., 2008; Dyr and Kostowski, 2008; Blednov et al., 2009; Tabakoff et al., 2009], to study the effects of alcohol abuse alone or in association with other drugs of abuse on behavior and growth [Knackstedt et al., 2006; Zou et al., 2009; Farook et al., 2009], and to identify the role of delta opioid receptors in alcohol-drinking behavior [Roberts et al., 2001]. The DID model is used quite commonly to mimic prenatal human binge drinking [Boehm et al., 2008].
C. Multiple bottles – free choice The animals have free access to rodent chow, and unrestricted choice between water and alcohol of varying concentrations [Yoneyama et al., 2008].
D. Drinking in the dark (DID) The animals have free access to rodent chow and unrestricted access to water except when alcohol is substituted for water for 2–4 h per day, usually 3 h into the dark cycle) [Rhodes et al., 2007; Ehringer et al., 2009].
Operant Models
In these models animals are trained to perform a certain task in order to self- administer alcohol orally, intravenously or directly into the stomach through surgically implanted catheters. The consumption of alcohol is initially initiated by providing a 10% solution of alcohol as the only available fluid several days before operant training, adulterants such sucrose or saccharin may be added to the alcohol solution to induce robust reliable self-administration [Green and Grahame, 2008].	Rodents and rhesus macaques	The Operant Models are mostly suited to study neurobiology of craving and reinforcing effects of alcohol [Koob 2000; Meyer 2000; Chu et al., 2007; Schwandt et al., 2010].
Alcohol in Agar
The animals have free access to rodent chow, alcohol containing agar and drinking water containing alcohol. Involves pair-feeding isocaloric amounts of rodent chow and agar containing dextrin/maltose [Bautista et al., 1995].	Rodents	The model has been used to study chronic alcohol abuse-induced disturbances in iron homeostasis [Gentry-Nielsen et al., 2001], cellular immune responses during retroviral infection [Sepúlveda et al., 2002], and to explore the mechanisms of alcohol-induced liver [Bautista et al., 1995, 1999, 1997, 2002] and muscle damage [Vary et al., 2002; 2008; Lang et al., 1999, 2004].
Alcohol in Agar diet
In this model the animals have free access to jellified liquid diet containing alcohol. Involves pair-feeding jellified isocaloric diet [Bykov et al., 2004].	Rodents	The model has been used to study mechanisms of alcohol-induced liver injury [Bykov et al., 2004; Ronis et al., 2004]
Alcohol vapor inhalation
The animals are maintained in special chambers in which a mixture of alcohol and air is pulsed via a mixing system [Le Bourhis, 1975, Gilpin et al., 2008].	Rodents	This model is suited for testing of somatic and motivational aspects of alcohol dependence and neurobiological mechanisms underlying chronic alcohol drinking, alcoholism, and abnormal alcohol-seeking behavior [Gilpin et al., 2008, 2009, Becker and Lopez 2004, Lopez and Becker 2005, Rimondini et al., 2003, Griffin WC III et al., 2009a, Dhaher et al., 2008, Finn et al., 2007].
Models of alcohol dependence
These models are usually a combination of two or more of the above described models of chronic alcohol abuse.	Rodents	These models have mostly been used for alcohol preference and dependence studies and for exploring the neurochemical, biochemical and immunological changes induced by binge drinking or chronic alcohol abuse. [Crews and Nixon 2009; Ward, 1987; Ward et al., 2009, Griffin WC 3rd et al., 2009b]
Second Hit Models for Alcoholic Disease
Published research suggests that gene- environment interactions [Whitcomb 2006; Stacey et al., 2009] play a major role in the pathogenesis and individual predisposition to alcoholic disease. Since laboratory models of alcohol abuse (First Hit) alone may not mimic all aspects of human alcoholic diseases, various “Second or Multiple Hit” models have been developed. These include superimposing nutritional, bacterial, viral, and hemodynamic factors, and/or using genetically manipulated rodents with the above models of alcohol abuse [Tsukamoto et al., 2009; Vonlaufen et al., 2007b; Gukovsky et al., 2008; Kono et al., 2001].	Rodents, guinea pigs, rabbits, pigs, and non-human primates	These models are used extensively to elucidate the mechanisms by which alcoholic diseases develop and progress.