Department of Pharmacology, Nanjing General Hospital of Nanjing Military Command, Nanjing 210002, Jiangsu, China.
J Ethnopharmacol. 2012 Jan 6;139(1):194-200. doi: 10.1016/j.jep.2011.11.004. Epub 2011 Nov 10.
As a well-known Chinese Materia Medica Rhizoma Anemarrhenae has multiple pharmacological activities including antipyretic, anti-inflammatory, anti-diabetic actions, etc. This study was designed to investigate effects of total saponins from Rhizoma Anemarrhenae (TS) on diabetes-associated cognitive decline in rats and influence on amyloid-beta (Aβ) levels in brain and inflammation.
Diabetic rats induced by intraperitoneal administration of streptozotocin, were randomized into two groups: diabetes and TS-treated diabetes. Blood glucose and body weight were measured monthly and weekly, respectively. After seven weeks, cognitive performances were evaluated with Morris water maze. Then, brain was obtained for assay of Aβ and TNF-α levels, and blood was collected for TNF-α assay.
Aβ(1-40), Aβ(1-42) and TNF-α levels were dramatically (all P<0.01) increased both in temporal cortex and hippocampus of diabetic rats, coupled with impairment of cognition, compared with those of the control. Chronic TS (200mg/kg) treatment markedly (P<0.05) improved the learning ability of diabetic rats, and significantly (all P<0.05) reduced Aβ(1-40), Aβ(1-42) and TNF-α levels in cortex as well as Aβ(1-40) level in hippocampus, whereas showed a decreased tendency for Aβ(1-42) and TNF-α levels in hippocampus. Moreover, eight-week treatment with TS remarkably (P<0.05) inhibited the elevation of TNF-α level in serum of diabetic rats, and significantly (both P<0.01) decrease the fasting blood glucose level and increase the body weight of diabectic rats.
Our findings demonstrate that diabetes-associated cognitive decline is, at least in part, due to brain Aβ accumulation in diabetic condition, and efficacy of TS to diabetes-associated cognitive decline in rats is a sum of reduction of Aβ accumulation and inflammation in brain as well as attenuation of major symptoms of diabetes.
作为一种著名的中药知母，具有多种药理活性，包括解热、抗炎、抗糖尿病等作用。本研究旨在探讨知母总皂苷（TS）对糖尿病相关认知功能下降大鼠的影响及其对脑内淀粉样β（Aβ）水平和炎症的影响。
通过腹腔注射链脲佐菌素诱导糖尿病大鼠，随机分为糖尿病组和 TS 治疗糖尿病组。每月测量血糖，每周测量体重。七周后，用 Morris 水迷宫评估认知表现。然后，取脑测定 Aβ和 TNF-α水平，取血测定 TNF-α水平。
糖尿病大鼠皮质和海马中 Aβ（1-40）、Aβ（1-42）和 TNF-α水平均显著升高（均 P<0.01），与对照组相比，认知功能受损。慢性 TS（200mg/kg）治疗显著改善糖尿病大鼠的学习能力（P<0.05），显著降低皮质中 Aβ（1-40）、Aβ（1-42）和 TNF-α水平，以及海马中 Aβ（1-40）水平（均 P<0.05），而对海马中 Aβ（1-42）和 TNF-α水平呈降低趋势。此外，TS 治疗 8 周显著抑制糖尿病大鼠血清 TNF-α水平升高（P<0.05），显著降低空腹血糖水平，增加糖尿病大鼠体重（均 P<0.01）。
我们的研究结果表明，糖尿病相关的认知功能下降至少部分是由于糖尿病状态下大脑 Aβ的积累，TS 对糖尿病相关认知功能下降大鼠的疗效是减少大脑 Aβ积累和炎症以及减轻糖尿病主要症状的总和。
