Gaspar Lauren, Bartman Sydney, Coppotelli Giuseppe, Ross Jaime M
George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, United States.
Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, United States.
Front Behav Neurosci. 2023 Aug 10;17:1182661. doi: 10.3389/fnbeh.2023.1182661. eCollection 2023.
Incidence of anxiety-like disorders in humans has been shown to decrease with aging; however, it is still under debate whether there are similarities in mice, which would support the use of mouse models in understanding the neuronal network changes that regulate anxiety-like behavior in aging. One of the most common tests used to assess anxiety-like behavior in laboratory animals is the elevated plus maze (EPM). Although several variables, such as room brightness and width of the maze arms, have been shown to influence the spontaneous animal behavior during the EPM test, none of these variables have ever been evaluated in aging to understand their possible differential effect on younger and older mice. We therefore decided to investigate the effect of apparatus construction on young adult and old mice of both sexes on EPM test performance. Our results show that distance traveled during the test is the variable that is most affected by apparatus characteristics independent of age and sex. We also found that apparatus construction was key in demonstrating that old mice spent more time and had relatively more entries in the open arms as compared to young mice, suggesting a decrease in anxiety-like behavior with age. Taken together, our data demonstrate that EPM apparatus characteristics dramatically affect test outcome with a wider arm apparatus being more effective in revealing age-dependent changes in anxiety-like behavior, thus, suggesting the use of a wider arm EPM when conducting aging studies in mice.
人类焦虑症的发病率已被证明会随着年龄增长而降低；然而，小鼠是否也存在类似情况仍存在争议，这将有助于利用小鼠模型来理解调节衰老过程中焦虑样行为的神经网络变化。用于评估实验动物焦虑样行为的最常用测试之一是高架十字迷宫（EPM）。尽管一些变量，如房间亮度和迷宫臂的宽度，已被证明会影响EPM测试期间动物的自发行为，但在衰老研究中，尚未对这些变量进行评估，以了解它们对年轻和老年小鼠可能产生的不同影响。因此，我们决定研究实验装置结构对成年雌雄小鼠EPM测试表现的影响。我们的结果表明，测试期间的移动距离是受装置特征影响最大的变量，且不受年龄和性别的影响。我们还发现，装置结构对于证明老年小鼠与年轻小鼠相比在开放臂中花费更多时间且进入次数相对更多至关重要，这表明焦虑样行为会随着年龄增长而减少。综上所述，我们的数据表明，EPM装置特征会显著影响测试结果，使用更宽臂的装置在揭示焦虑样行为的年龄依赖性变化方面更有效，因此，建议在对小鼠进行衰老研究时使用更宽臂的EPM。
