茯苓多糖对痴呆小鼠学习记忆功能的保护作用及其机制

谢云亮; 张博

doi:10.13386/j.issn1002-0306.2023120320

茯苓多糖对痴呆小鼠学习记忆功能的保护作用及其机制

谢云亮,
张博

Protective Effect of Poria cocos Polysaccharides on the Learning and Memory Function and Its Mechanism in Dementia Mice

摘要

摘要: 目的：探究茯苓多糖保护东莨菪碱致痴呆小鼠学习记忆功能的作用及机制，为痴呆的防治提供新的思路。方法：小鼠分为正常组、模型组、茯苓多糖低剂量组（50 mg/kg）、茯苓多糖高剂量组（100 mg/kg）及多奈哌齐组（1 mg/kg），连续灌胃28 d，并从第24 d开始连续5 d腹腔注射东莨菪碱（1 mg/kg）。通过水迷宫试验检测学习记忆能力，苏木素伊红（hematoxylin and eosin，HE）染色检测海马组织病理变化，TUNEL染色检测海马组织细胞凋亡，实时定量PCR法检测海马组织凋亡相关基因表达，酶联免疫吸附法（enzyme-linked immunosorbent assay，ELISA）检测海马组织中枢胆碱能系统指标与氧化应激指标，Western blot法检测海马组织Kelch样环氧氯丙烷相关蛋白1（Kelch-like ECH-associated protein 1，Keap1）、核因子E2相关因子2（nuclear factor erythroid 2-related factor 2，Nrf2）及血红素加氧酶-1（heme oxygenase-1，HO-1）蛋白表达。结果：与模型组比较，茯苓多糖低、高剂量组逃避潜伏期缩短（P<0.01），目标象限停留时间及穿越平台次数增加（P<0.01），海马组织病理形态减轻；神经元细胞凋亡率下降（P<0.05，P<0.01），B细胞淋巴瘤-2（B cell lymphoma-2，Bcl-2）mRNA表达、乙酰胆碱转移酶（choline acetyltransferase，ChAT）活性及乙酰胆碱（acetylcholine，ACH）含量增加（P<0.05，P<0.01），Bcl-2相关X蛋白（Bcl-2 associated X protein，Bax） mRNA表达及乙酰胆碱酯酶（acetylchohnesterase，AChE）活性降低（P<0.05，P<0.01）；谷胱甘肽过氧化物酶（glutathione peroxidase，GSH-Px）、超氧化物歧化酶（superoxide dismutase，SOD）活性及Nrf2、HO-1表达升高（P<0.01），丙二醛（malondialdehyde，MDA）含量及Keap1表达下降（P<0.05，P<0.01）。结论：茯苓多糖具有保护痴呆小鼠学习记忆功能的作用，抗神经元细胞凋亡、调节中枢胆碱能系统功能及抑制氧化应激是其发挥保护作用的潜在机制。

Abstract: Objective: The protective effect of Poria cocos polysaccharides (PCPs) on the learning and memory function of scopolamine-induced dementia mice and its mechanism were explored, which was expected to provide a new idea for the prevention and treatment of dementia. Methods: Mice were divided into control group, model group, low-dose PCPs group (50 mg/kg), high-dose PCPs group (100 mg/kg), and donepezil group (1 mg/kg). The mice were administered by gavage once daily, continuously for 28 d, in which mice except those in the control group were intraperitoneally injected with scopolamine (1 mg/kg) from the 24^th d, successively for 5 d. The learning and memory function of mice were observed by water maze test, the pathological changes in the hippocampal tissue were examined by hematoxylin and eosin (HE) staining, the apoptosis of hippocampal cells was observed by TUNEL staining, the expression of hippocampal apoptosis-related genes was detected by real-time quantitative PCR, the hippocampal central cholinergic system indicators and oxidative stress indicators were detected by enzyme-linked immunosorbent assay (ELISA), and the expression of Kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the hippocampal tissue was detected by Western blot. Results: Compared with that in the model group, the escape latency of mice in low-dose and high-dose PCPs groups was shortened (P<0.01), the residence time in the target quadrant was prolonged and the number of times of crossing platform was increased (P<0.01), and the pathological change in the hippocampus tissue was alleviated, the apoptosis rate of neurons was reduced (P<0.05, P<0.01), the mRNA expression of B cell lymphoma-2 (Bcl-2), the activity of choline acetyltransferase (ChAT) and the content of acetylcholine (ACH) were increased (P<0.05, P<0.01), the mRNA expression of Bcl-2 associated X protein (Bax) and the activity of acetylchohnesterase (AChE) were reduced (P<0.05, P<0.01), the activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) and the expression of Nrf2 and HO-1 were increased (P<0.01), the content of malondialdehyde (MDA) and the expression of Keap1 were decreased (P<0.05, P<0.01). Conclusion: PCPs could protect the learning and memory function of scopolamine-induced dementia mice, and its mechanism would be related to its anti-apoptosis of neurons, regulation of central cholinergic system and inhibition of oxidative stress.