高级检索

二氢麦角胺改善阿尔茨海默病状态下的突触萎缩及其对认知功能的影响

Dihydroergotamine ameliorates synaptic atrophy in Alzheimer’s disease states and its effect on cognitive function

  • 摘要: 研究表明突触损伤与认知功能障碍密切相关,狐猴酪氨酸激酶1(LMTK1)是影响突触生长的关键性激酶。二氢麦角胺(DHE)是一种生物活性较高的麦角生物碱衍生物,它对认知、记忆处理和运动控制具有一定的调节作用。本研究旨在探讨DHE对阿尔茨海默病(AD)模型动物突触形态和可塑性及认知功能的影响。4月龄SAMR1小鼠作为对照(n = 12),4月龄SAMP8小鼠被随机分为3组(每组12只):AD组、DHE低剂量组以及高剂量组,连续8周每日腹腔注射DHE注射液或生理盐水。采用免疫荧光、高尔基染色、电生理、Morris水迷宫以及Western blot实验研究DHE对AD模型小鼠突触形态、突触可塑性、认知功能以及LMTK1下游TBC1D9B磷酸化水平的影响。构建沉默和过表达LMTK1的C17.2细胞,运用免疫荧光实验研究DHE对LMTK1沉默和过表达后神经细胞突触长度的影响。免疫荧光实验结果显示SAMP8小鼠给予DHE后,突触后标记物PSD95显著增加,这提示DHE可以增加AD小鼠海马体突触密度;高尔基染色实验结果表明,AD模型小鼠海马内突触发生萎缩,而高剂量组DHE显著改善了突触萎缩;电生理实验结果表明,与正常小鼠相比,AD模型小鼠长时程增强(LTP)水平明显降低(P < 0.000 1),而DHE给药后LTP显著改善;Morris水迷宫实验结果进一步表明,DHE可以改善AD小鼠的认知障碍;Western blot实验结果表明,AD小鼠海马内P-LMTK1水平显著增加,DHE给药后,其下游效应蛋白P-TBC1D9B水平显著降低;体外细胞免疫荧光实验结果表明,DHE显著改善了过表达LMTK1的神经细胞的突触萎缩,而当LMTK1沉默后,其改善作用消失。本研究提示DHE可能通过作用于LMTK1改善AD状态下的突触萎缩及认知功能障碍。

     

    Abstract: Studies suggest that synaptic damage is closely associated with cognitive dysfunction, and lemur tyrosine kinase 1 (LMTK1) is a key kinase that affects synaptic growth. Dihydroergotamine (DHE) is an ergot alkaloid derivative with high biological activity, which could regulate cognition, memory processing and motor control.This study aims to investigate the effect of DHE on synapse atrophy and plasticity as well as cognition in Alzheimer’s disease (AD) model animals.SAMR1 mice were selected as control group (n = 12).SAMP8 mice were randomly divided into 3 groups (n = 12 for each group):AD group, DHE low-dose group and high-dose group.The DHE groups were injected DHE intraperitoneally daily for 8 weeks.Immunofluorescence experiments, Golgi staining experiment, electrophysiological experiment, Morris water maze experiment (MWM) and Western blot experiment were conducted to investigate the effect of DHE on synaptic morphology, synaptic plasticity, cognitive function as well as the phosphorylation level of LMTK1 downstream TBC1D9B in AD model mice.Subsequently, the LMTK1 silencing and overexpression cells were constructed.Immunofluorescence experiments were used to study the effect of DHE on synaptic length of nerve cell after LMTK1 silencing and overexpression.In the hippocampus of AD mice, the postsynaptic marker PSD95 was significantly increased after DHE administration, which suggested that DHE could increase the synaptic density. In Golgi staining experiment, synaptic atrophy was observed in the hippocampal of AD mice, which could be improved by high-dose DHE.Compared with normal mice, the long-term potentiation (LTP) level of AD model mice was significantly reduced (P < 0.000 1), DHE could increase LTP significantly.The MWM experiment further showed that DHE could improve cognitive function in AD mice.WB experiments showed that the level of P-LMTK1 in the hippocampus of AD mice increased significantly, and the level of downstream P-TBC1D9B decreased significantly after DHE administration.Cell immunofluorescence experiments in vitro had shown that DHE significantly improved synaptic atrophy in overexpressed C17.2 cells, while its improvement disappeared when LMTK1 was silenced. This research suggests DHE may improve synaptic atrophy and cognitive dysfunction in AD by targeting on LMTK1.

     

/

返回文章
返回