Tong Hui, Chen Gui-Hai, Liu Rong-Yu, Zhou Jiang-Ning
Anhui Geriatric Institute, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, 230022 PR China.
Physiol Behav. 2007 Jun 8;91(2-3):290-8. doi: 10.1016/j.physbeh.2007.03.008. Epub 2007 Mar 16.
The memory impairment induced by adult-onset hypothyroidism is a common symptom. However, the exact onset time that will influence on memory function is still an issue of debate. The purpose of this study is to determine the onset effect of hypothyroidism on the memory during adulthood. Three age groups of Kunming (KM) mice were used, including 2, 8, and 15-month-old mice. Adult-onset hypothyroidism was made by adding PTU to drinking water and hypothyroid states were documented by the measurement of serum thyroid hormones level. A battery of tasks, i.e. novel-object recognition, olfactory discrimination, Morris water maze, was used to test mice's memory. The results showed that adult-onset hypothyroidism induced the impairment of odor and spatial memory consolidation whereas it did not affect visual memory encoding or consolidated spatial memory retention. Age at onset of hypothyroidism was an important factor for the memory impairment induced by hypothyroidism. The 2-month-old hypothyroid mice had significantly impaired abilities in both the olfactory discrimination and the spatial cognitive tasks relative to the 2-month-old controls. The 8-month-old hypothyroid mice had only impaired ability in the spatial cognitive task relative to the same age controls. The 15-month-old hypothyroid mice retained these cognitive abilities relative to the same age controls. These results suggested that adult-onset hypothyroidism could induce an age- and task-dependent impairment of memory in female KM mice.
成年期甲状腺功能减退引起的记忆障碍是一种常见症状。然而，影响记忆功能的确切发病时间仍是一个有争议的问题。本研究的目的是确定成年期甲状腺功能减退对记忆的发病影响。使用了三个年龄组的昆明（KM）小鼠，包括2、8和15月龄的小鼠。通过在饮用水中添加丙硫氧嘧啶（PTU）诱导成年期甲状腺功能减退，并通过测量血清甲状腺激素水平记录甲状腺功能减退状态。使用一系列任务，即新物体识别、嗅觉辨别、莫里斯水迷宫，来测试小鼠的记忆。结果表明，成年期甲状腺功能减退会导致气味和空间记忆巩固受损，而不影响视觉记忆编码或巩固的空间记忆保持。甲状腺功能减退的发病年龄是甲状腺功能减退引起记忆障碍的一个重要因素。相对于2月龄的对照组，2月龄的甲状腺功能减退小鼠在嗅觉辨别和空间认知任务中的能力均显著受损。相对于同年龄对照组，8月龄的甲状腺功能减退小鼠仅在空间认知任务中能力受损。相对于同年龄对照组，15月龄的甲状腺功能减退小鼠保留了这些认知能力。这些结果表明，成年期甲状腺功能减退可在雌性KM小鼠中诱导年龄和任务依赖性的记忆障碍。
