Hypothyroidism causes learning and memory impairment. Considering the neuroprotective properties of thiamine (Vitamin B1), this study was conducted to investigate the effects of thiamine on acetylcholinesterase (AChE) activity, oxidative damage, and memory deficits in hypothyroid rats.

In this study, 50 rats (21 days old) were randomly divided into 5 groups and treated with propylthiouracil (0.05% in drinking water) and thiamine (50, 100, and 200 mg/kg, oral) for 7 weeks. Following that, Morris water maze (MWM) and passive avoidance (PA) tests were performed. Finally, oxidative stress indicators and AChE activity were measured in brain tissue.

Treatment of hypothyroid rats with thiamine, especially at 100 and 200 mg/kg, alleviated the ability to remember the location of the platform as reflected by less time spent and distance to reach the platform, during the MWM test (P < 0.05 to P < 0.001). In the PA test, the latency to enter the dark chamber and light stay time were increased in rats who received thiamine compared to the hypothyroid group (P < 0.05 to P < 0.001). In addition, thiamine increased the levels of total thiol groups and superoxide dismutase while decreasing the levels of malondialdehyde and AChE.

Our results suggest that thiamine supplementation could effectively improve memory loss in a rat model of hypothyroidism. The positive effects of thiamin on the learning and memory of hypothyroid rats may be due to amelioration of redox hemostasis and cholinergic disturbance.

甲状腺功能减退症会导致学习和记忆障碍。考虑到硫胺素（维生素 B1）的神经保护特性，本研究旨在探讨硫胺素对甲状腺功能减退大鼠乙酰胆碱酯酶 (AChE) 活性、氧化损伤和记忆缺陷的影响。

在这项研究中，50只大鼠（21天龄）被随机分为5组，并用丙硫氧嘧啶（0.05%饮用水）和硫胺素（50、100和200 mg/kg，口服）治疗7周。随后进行莫里斯水迷宫（MWM）和被动回避（PA）测试。最后，测量脑组织中的氧化应激指标和乙酰胆碱酯酶活性。

用硫胺素治疗甲状腺功能减退大鼠，特别是在 100 和 200 mg/kg 剂量下，可减轻记住平台位置的能力，这反映在 MWM 测试期间花费的时间和到达平台的距离更少（P < 0.05 至 P < 0.001）。在PA测试中，与甲状腺功能减退组相比，接受硫胺素治疗的大鼠进入暗室的潜伏期和光停留时间增加（P < 0.05至P < 0.001）。此外，硫胺素还增加了总硫醇基团和超氧化物歧化酶的水平，同时降低了丙二醛和乙酰胆碱酯酶的水平。

我们的结果表明，补充硫胺素可以有效改善甲状腺功能减退大鼠模型的记忆丧失。硫胺素对甲状腺功能减退大鼠学习记忆的积极作用可能是由于改善氧化还原止血和胆碱能紊乱所致。