Objective: To establish a model of long-term free drinking mouse by feeding mice with alcohol to simulate the state of human voluntary long-term drinking, and on this basis, to further discuss the evaluation criteria of long-term free drinking mice model in sports, anxiety and cognitive behavior.
Methods: Forty six-week-old SPF C57BL/6 male mouse were randomly divided into two groups: Long-term free drinking group (n=20) and normal control group (n=20). The two groups were given solid feed normally. The long-term free drinking group was free to take 10% alcohol and water every day, while the normal drinking group only took water every day. The mice were fed for 7 months, and were evaluated by a series of behavioral methods, including Rota-rod test, balance beam test, open filed test, the elevated plus maze, two-box social behavior, new object recognition, Y maze and water maze.
Results: With the increase of drinking days, the mice showed significant alcohol addiction in the alcohol preference test. With the increase of alcohol intake, the mice in the long-term free choice drinking group had slightly shiny fur and reduced diet. Compared with the control group, the weight gain began to slow down from the third month, and the weight decreased significantly by the sixth and seventh months (P=0.006, P < 0.001). The mice showed reduced balance locomotion ability (P=0.003, P=0.001) in the rotary bar and balance beam test. In the open field and elevated cross test, the mice had obvious anxiety-like behavior (P < 0.001). The mice showed decreased social ability in the two boxes of social behavior (P < 0.016). In the experiment of new object recognition and Y maze, the exploration of new object decreased (P=0.018, P=0.040). In the water maze, cognitive functions, such as learning and spatial memory were reduced (P < 0.001).
Conclusion: The successful establishment of the long-term free drinking mouse model is more convenient for us to carry out further research on the neural mechanism of alcohol addiction, and lays an experimental foundation for exploring the neural mechanism of alcohol addiction and related new targets.
目的: 建立长期自由饮酒小鼠的模型模拟人类自愿长期饮酒的状态，探讨长期自由饮酒小鼠模型在运动、焦虑及认知行为方面的评价标准。
方法: 使用6周龄SPF级C57BL/6J雄性小鼠40只，随机分为长期自由饮酒组(n=20)和正常对照组(n=20)。两组小鼠固体饲料正常给予，长期自由饮酒组小鼠每日自由摄取10% (体积分数)酒精和水, 正常对照组每日仅摄取水。饲养时间为7个月，并应用转棒实验、平衡木、矿场、高架十字、两箱社交行为学、新物体识别、Y迷宫、水迷宫等行为学测试对模型小鼠进行评价，每次进行行为学测试前需进行24 h的酒精戒断。
结果: 随着饮酒天数的增加，在酒精偏好性测试中小鼠表现出明显嗜酒现象，长期自由选择饮酒组小鼠随着酒精摄入的增加，皮毛略有光泽，饮食量减少，与对照组相比，从第3个月开始体质量增加有减缓的趋势，在第6个月和第7个月时体质量显著降低(P=0.006，P < 0.001)；在转棒和平衡木实验中小鼠表现出平衡运动能力减弱(P=0.003，P=0.001)；在旷场和高架十字实验中小鼠有明显的焦虑样行为(P < 0.001)；在两箱社交行为学测试中小鼠社交能力减少(P < 0.016)；在新物体识别和Y迷宫实验测试中表现出对新物体的探索降低(P=0.018，P=0.040)；在水迷宫中表现出学习和空间记忆等认知功能减弱(P < 0.001)。
结论: 成功建立长期自由饮酒小鼠模型，为酒精成瘾的神经机制以及相关新靶点研究奠定了实验动物模型基础。
Keywords: Animal behavior; Free drinking; Long-term; Mice model.