Objective: Prolonged diabetes mellitus causes impairments of cognition and attentional dysfunctions. Diosgenin belongs to a group of steroidal saponins with reported anti-diabetic and numerous protective properties. This research aimed to assess the effect of diosgenin on beneficially ameliorating learning and memory decline in a rat model of type 1 diabetes caused by streptozotocin (STZ) and to explore its modes of action including involvement in oxidative stress and inflammation.Methods:Rats were assigned to one of four experimental groups, comprising control, control under treatment with diosgenin, diabetic, and diabetic under treatment with diosgenin. Diosgenin was given daily p.o. (40 mg/kg) for 5 weeks. Results: The administration of diosgenin to the diabetic group reduced the deficits of functional performance in behavioral tests, consisting of Y-maze, passive avoidance, radial arm maze, and novel object discrimination tasks (recognitive). Furthermore, diosgenin treatment attenuated hippocampal acetylcholinesterase activity and malon­dialdehyde, along with improvement of antioxidants such as superoxide dismutase and glutathione. Meanwhile, the hippocampal levels of inflammatory indicators, namely interleukin 6, nuclear factor-κB, toll-like receptor 4, tumor necrosis factor α, and astrocyte-specific biomarker glial fibrillary acidic protein, were lower and, on the other hand, tissue levels of nuclear factor (erythroid-derived 2)-related factor 2 were elevated upon diosgenin administration. Besides, the mushroom-like spines of the pyramidal neurons of the hippocampal CA1 area decreased in the diabetic group, and this was alleviated following diosgenin medication. Conclusions: Taken together, diosgenin is capable of ameliorating cognitive deficits in STZ-diabetic animals, partly due to its amelioration of oxidative stress, inflammation, astrogliosis, and possibly improvement of cholinergic function in addition to its neuroprotective potential.
Neuropsychobiology

中文翻译：

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薯蓣皂苷元减轻链脲佐菌素诱导的糖尿病大鼠的认知障碍：潜在机制。

目的：长期糖尿病会导致认知障碍和注意力障碍。薯蓣皂苷属于一组甾体皂苷，据报道具有抗糖尿病和多种保护特性。本研究旨在评估薯蓣皂苷元对链脲佐菌素 (STZ) 引起的 1 型糖尿病大鼠模型学习和记忆力下降的有益改善作用，并探索其作用模式，包括参与氧化应激和炎症。方法：大鼠被分配到四个实验组之一，包括对照、用薯蓣皂苷元治疗的对照、糖尿病和用薯蓣皂苷元治疗的糖尿病。每天口服薯蓣皂苷元 (40 mg/kg)，持续 5 周。结果：向糖尿病组施用薯蓣皂苷元减少了行为测试中功能表现的缺陷，包括 Y 型迷宫、被动回避、径向臂迷宫和新的物体辨别任务（认知）。此外，薯蓣皂苷元处理减弱了海马乙酰胆碱酯酶活性和丙二醛，同时改善了抗氧化剂，如超氧化物歧化酶和谷胱甘肽。同时，炎症指标，即白细胞介素 6、核因子-κB、toll 样受体 4、肿瘤坏死因子 α 和星形胶质细胞特异性生物标志物胶质纤维酸性蛋白的海马水平较低，另一方面，组织水平给予薯蓣皂苷元后，核因子（红细胞衍生的 2）相关因子 2 的浓度升高。除了，结论：总而言之，薯蓣皂苷元能够改善 STZ 糖尿病动物的认知缺陷，部分原因在于其改善氧化应激、炎症、星形胶质细胞增生，并可能改善胆碱能功能以及其神经保护潜力。
神经心理生物学