a Laboratory of Nutrition and Behavior , FFCLRP-USP , Avenida Bandeirantes, 3900, 14040-901, Ribeirão Preto- SP , Brazil.
Nutr Neurosci. 1998;1(4):295-303. doi: 10.1080/1028415X.1998.11747239.
The interaction between the effects of different levels of protein malnutrition and environmental stimulation was investigated in young male rats in the elevated plus-maze (EPM). Litters (dam plus 6 male and 2 female pups) were fed a 16% (
C), 10% (Malnourished: M10) or 6% (Malnourished: M6) protein diet. Half of the litters were daily exposed to additional stimulation (CS, MS10 or MS6), while the other half was maintained in normal rearing conditions (CN, MN10 or MN6). The stimulation (handling) consisted of holding the rat in one hand and gently touching the dorsal part of the body with the fingers for 3 min. On the 22nd day of life (weaning), two male pups from each group were tested in the plus-maze. Two male pups continued to receive the same diet as their mothers, and the other two were fed a non-purified lab chow diet until 35 days of age when they were tested in the plus-maze (LN, LS, LN10, LS10, LN6 and LS6 groups). Results showed that environmental stimulation increased open arms exploration both at 22 and 35 days of age, indicating an anxiolytic effect of this procedure. Younger rats (22 days of age) explored significantly more the open arms of the maze as compared with older rats (35 days of age), indicating an increase in anxiety with age. M6 animals showed significantly higher percentages of open arm entries and less frequent attempts to enter open arms in the maze as compared with C and M10 animals. These results suggest that even a short period of protein deficiency can produce alterations in the emotional response of rats in the elevated plus-maze. In addition, the data demonstrated that protein deficiency more severe than 10% is necessary to produce behavior alterations in the EPM test.
本研究旨在探讨不同程度蛋白质营养不良与环境刺激对雄性幼鼠高架十字迷宫（EPM）行为的交互作用。将孕鼠（外加 6 只雄性和 2 只雌性幼鼠）分为 4 组，分别喂养 16%（对照组：C）、10%（蛋白质缺乏组：M10）或 6%（蛋白质缺乏组：M6）蛋白饮食。一半的幼鼠接受每日环境刺激（CS、MS10 或 MS6），另一半则维持正常饲养条件（CN、MN10 或 MN6）。刺激（处理）方法为用一只手握住幼鼠，并用手指轻轻触摸背部 3 分钟。在第 22 天（断奶），每组取两只雄性幼鼠进行高架十字迷宫测试。两组雄性幼鼠继续喂食与其母鼠相同的饮食，其余两组则喂食非纯化的实验室鼠粮，直至 35 日龄时进行高架十字迷宫测试（LN、LS、LN10、LS10、LN6 和 LS6 组）。结果显示，环境刺激增加了幼鼠在第 22 天和 35 天的开臂探索，表明该处理具有抗焦虑作用。与 35 日龄的幼鼠相比，22 日龄的幼鼠更倾向于探索迷宫的开臂，表明随着年龄的增长，焦虑感增加。与 C 和 M10 组相比，M6 组的幼鼠进入开臂的比例明显更高，进入开臂的尝试次数明显更少。这些结果表明，即使是短暂的蛋白质缺乏也会导致高架十字迷宫中大鼠的情绪反应发生改变。此外，数据表明，只有在严重蛋白质缺乏（超过 10%）的情况下，EPM 测试才会出现行为改变。
