灵芝多糖对D-半乳糖诱导衰老小鼠海马神经元的保护作用

Protective effects of Ganoderma lucidum polysaccharides on hippocampal neurons in the D-galactose-induced aging mice

目的:研究灵芝多糖(GLPs)对D-半乳糖(D-gal)诱导的衰老小鼠海马神经元的保护作用和调控机制。方法:将30只雄性C57BL/6J小鼠随机分为3组:对照组(Control)、衰老模型组(D-gal)、衰老+灵芝多糖给药组(D-gal+GLPs)。连续腹腔注射D-gal建立衰老小鼠模型,治疗组小鼠在造模两周后给予腹腔注射GLPs。通过Morris水迷宫实验检测各组小鼠空间学习记忆能力;HE染色、尼氏染色及透射电镜观察评估海马神经元病理改变;试剂盒测定海马总抗氧化能力(T-AOC)水平、还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)活性水平;Western Blot检测海马核转录因子红系2相关因子2(Nrf2)、Kelch样环氧氯丙烷相关蛋白1(Keap-1)、血红素加氧酶1(HO-1)、线粒体融合蛋白2(Mfn2)和线粒体裂变相关蛋白1(Drp1)的蛋白表达水平。结果:与模型组相比,D-gal+GLPs组小鼠空间学习记忆能力明显增强(P<0.05);海马区神经元固缩、数量减少及异常分布明显改善,尼氏体增加,神经元及线粒体结构损伤明显改善。GLPs处理后可显著提高衰老小鼠海马总抗氧化能力和GSH/GSSG比值。此外,GLPs治疗后Nrf2、HO-1、Mfn2蛋白表达水平明显增加(P<0.05),而Keap-1、Drp1蛋白表达水平较D-gal组小鼠显著降低(P<0.05)。结论:GLPs能够有效缓解D-gal诱导的衰老小鼠海马神经元损伤并提高小鼠的学习记忆能力,其主要通过Nrf2/HO-1通路提高海马抗氧化能力并维持神经元线粒体正常结构功能来发挥神经保护作用。

Objective:To investigate the mechanism of protective effect of Ganoderma lucidum polysaccharides(GLPs)on hippocampal neurons in the D-galactose(D-gal)-induced aging mice.Methods:Thirty male C57 BL/6 J mice were stochastically divided into 3 groups:Control group,D-gal group and D-gal+GLPs group.The aging mouse model was established by intraperitoneal injection of D-gal,and mice in the GLPs treatment group were intraperitoneally injected with GLPs.The spatial learning and memory ability of mice in each group was detected by Morris water maze test;HE staining,Nissl staining and transmission electron microscopy were used to evaluate the morphological changes of hippocampal neurons;the levels of total antioxidant capacity(T-AOC)content,reduced glutathione(GSH)disulfide and oxidized glutathione(GSSG)disulfide of mouse hippocampus were determined by kits.The expressions of nuclear factor erythroid 2-related factor 2(Nrf2),Kelch-like epichlorohydrin-related protein 1(Keap-1),heme oxygenase 1(HO-1),mitofusion2(Mfn2),and dynein-related protein 1(Drp1)were detected by Western Blot.Results:After GLPs treatment,the spatial learning and memory abilities of mice were significantly enhanced than the D-gal group(P<0.05),the pyknotic state,number reduction and abnormal distribution of neurons in the hippocampus were significantly improved,the Nissl bodies were increased,and the structural damage of neurons and mitochondria was significantly improved.The total antioxidant capacity and the expressions of hippocampal Nrf2,HO-1 and Mfn2 of D-gal+GLPs group were tremendously higher than those in the D-gal group(P<0.05).The expressions of Keap-1 and Drp1 were significantly lower than those in the D-gal group(P<0.05).Conclusion:GLPs can effectively alleviate D-gal-induced hippocampal neuron damage in aging mice and improve the learning and memory ability of mice,mainly through the Nrf2/HO-1 pathway to resisting oxidative stress and maintain the dynamics of neuronal mitochondria to exert neuroprotective effects.