右美托咪啶通过抑制NADPH氧化酶2缓解氧化应激小鼠模型神经元的毒性和认知障碍的机制

摘要 目的：探讨右美托咪啶通过抑制NADPH氧化酶2缓解氧化应激小鼠模型神经元的毒性和认知障碍的机制。方法：10只野生型以及20只Sod1KO雄性BALB/c小鼠,12月龄,根据实验目的分为3组：对照组（野生型小鼠）,模型组（氧化应激小鼠模型）和DEX组（氧化应激小鼠模型+50 μg/kg DEX治疗）,每组10只。通过MWM 测试检测小鼠的空间学习和记忆能力。通过免疫染色检测海马中Neu-N+细胞数和PSD-95表达水平。通过蛋白质印迹检测海马中Neu-N、PSD-95、TH、总α-突触核蛋白和Ser129-磷酸化α-突触核蛋白表达水平。通过ROS、MDA和SOD检测试剂盒分别检测ROS、MDA和SOD水平。通过 ELISA试剂盒检测NOX2水平。通过RT-qPCR检测IL-1β、IL-6和TNF-α水平。结果：对照小鼠表现出正常的空间学习功能,与对照组小鼠相比,模型组小鼠逃避潜伏期和游泳距离增加（P<0.05）,而DEX治疗能够降低模型组小鼠逃避潜伏期和游泳距离（P<0.05）。三组小鼠平均游泳速度没有统计性差异（P>0.05）。与对照组小鼠相比,模型组小鼠小鼠海马中Neu-N+细胞数和PSD-95表达水平降低（P<0.05）,而DEX治疗能够增加小鼠海马中Neu-N+细胞数和PSD-95表达水平（P<0.05）。与对照组小鼠相比,模型组小鼠小鼠海马中Neu-N、PSD-95和TH蛋白表达水平降低（P<0.05）,总α-突触核蛋白和Ser129-磷酸化α-突触核蛋白表达水平升高（P<0.05）,而DEX治疗能够增加小鼠海马中Neu-N、PSD-95和TH蛋白表达水平（P<0.05）,降低总α-突触核蛋白和Ser129-磷酸化α-突触核蛋白表达水平（P<0.05）。与对照组小鼠相比,模型组小鼠ROS和MDA水平增加,SOD水平降低（P<0.05）,而DEX治疗能够降低ROS和MDA水平,增加SOD水平（P<0.05）。与对照组小鼠相比,模型组小鼠NOX2水平增加（P<0.05）,而DEX治疗能够降低NOX2水平（P<0.05）。与对照组小鼠相比,模型组小鼠IL-1β、IL-6和TNF-α水平增加（P<0.05）,而DEX治疗能够降低IL-1β、IL-6和TNF-α水平（P<0.05）。结论：DEX对NOX2的抑制可通过抑制小鼠模型中的氧化应激和神经炎症来阻断学习和记忆障碍以及海马神经变性。     

锁阳乙酸乙酯提取物改善慢性应激小鼠认知功能障碍的神经保护机制

本实验以去卵巢后慢性应激模型,探究锁阳乙酸乙酯提取物(ECS)改善慢性应激小鼠认知功能障碍的神经保护机制。采用Morris水迷宫检测小鼠空间学习记忆能力,Western Blot检测海马组织突触蛋白中突触囊泡蛋白(synaptophysin,Syn)和突触后致密物(Postsynaptic density protein 95,PSD-95)表达量,通过海马组织形态学改变进一步证明ECS的神经保护作用。Morris水迷宫结果显示雌鼠锁阳乙酸乙酯组穿越平台次数增加(P0.01)。Western Blot结果显示,ECS可增加Syn(P0.05)与PSD-95(P0.05)蛋白表达量。HE染色结果显示ECS可减轻海马神经元损伤,改善海马CA1区锥体细胞形态。结果表明ECS能够增加去势后慢性应激小鼠突触蛋白中Syn与PSD-95的表达量,保护海马神经元,改善慢性应激所致学习记忆障碍。     

丙泊酚对老年大鼠的认知功能障碍及海马神经元凋亡的影响

摘要 目的：探讨丙泊酚对老年大鼠的认知功能障碍及海马神经元凋亡的影响。方法：选择45只老年大鼠随机分为3组,包括对照组、七氟烷组、联合组,七氟烷组吸入1.5%七氟烷,吸入频次为1 h/d;联合组则给予1.5%七氟烷、丙泊酚注射液150 mg/kg,对照组则等量注射氯化钠溶液,3组均进行为期2周的给药时间。进行Morris水迷宫试验,对海马神经元凋亡蛋白,血清白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）水平,PI3K/Akt/ mTOR通路蛋白相对表达予以检测。结果：Morris水迷宫试验2、3 d时潜伏期、游泳距离比Morris水迷宫试验1 d时缩短,七氟烷组Morris水迷宫试验1、2 d时潜伏期比对照组延长,Morris水迷宫试验1、2 d时游泳距离比对照组延长,联合组第1、2、3 d潜伏期比七氟烷组缩短,游泳距离比七氟烷组缩短（P<0.05）;与对照组相比,七氟烷组Bax蛋白、Capase-3蛋白相对表达水平升高,Bcl-2蛋白相对表达水平下降;与七氟烷组相比,联合组Bax蛋白、Capase-3蛋白相对表达水平下降,Bcl-2蛋白相对表达水平上升（P<0.05）;七氟烷组血清IL-6、TNF-α、IL-1β水平比对照组高,联合组血清IL-6、TNF-α、IL-1β水平比七氟烷组低（P<0.05）;七氟烷组p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR通路蛋白相对表达比对照组低,联合组p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR通路蛋白相对表达比七氟烷组高（P<0.05）。结论：丙泊酚可有效缓解七氟烷引起的老年大鼠神经受损状况,其与该药物通过对炎症反应与海马细胞凋亡的抑制,对PI3K/Akt/ Mtor信号通路进行激活有关。     

AD认知功能障碍的代谢紊乱机制:脑胰岛素抵抗及其介导的PI3K/Akt信号通路受损

阿尔茨海默病(Alzheimer’s disease, AD)是一种以进行性痴呆为主要特征的中枢神经系统退行性疾病,其认知功能障碍可能与Ⅱ型糖尿病(type 2 diabetes, T2DM)诱发的胰岛素抵抗所损伤的PI3K/Akt胰岛素信号级联通路相关。胰岛素是调节机体新陈代谢的重要激素,通过与神经细胞表面的胰岛素受体结合激活PI3K/Akt信号通路,以调控葡萄糖、脂质的代谢。任何中间媒介功能紊乱所导致的脑胰岛素水平和胰岛素敏感性的降低都会损坏PI3K/Akt信号通路,诱发脑能量代谢障碍、Aβ沉积、Tau蛋白过度磷酸化,引起并加重AD认知功能障碍。因此,本文以PI3K/Akt胰岛素信号通路为主线,揭示了T2DM中脑胰岛素抵抗(insulin resistance, IR)与AD之间的复杂机制,旨在加深对脑IR介导的AD病理过程的系统性理解,借此为延缓或治疗AD的认知功能障碍提供理论基础。     

川续断皂苷Ⅵ对睡眠剥夺小鼠神经发生及认知功能的改善作用研究CSCD

本文旨在探讨川续断皂苷Ⅵ(asperosaponin Ⅵ,ASA Ⅵ)对睡眠剥夺小鼠认知功能的改善作用及相关机制。采用多平台水环境法对C57BL/6J小鼠进行睡眠剥夺,期间腹腔注射ASA Ⅵ进行干预,采用新物体识别实验及Morris水迷宫实验评估小鼠的认知功能,运用q-PCR、免疫组化、Western blotting分别检测小鼠海马区的炎症水平、神经发生及信号通路变化。结果显示:与对照组相比,模型组小鼠海马中的小胶质细胞呈激活状态,炎症因子的表达水平显著提高(P<0.05),新生神经元数量显著减少(P<0.05),并导致认知功能下降。ASA Ⅵ干预显著改善了睡眠剥夺小鼠的认知功能,抑制海马中促炎性细胞因子IL-1β、TNF-α和IL-6的表达(P<0.05),同时显著提高抗炎性细胞因子IL-4、IL-10和神经营养因子BDNF的表达水平(P<0.05)。ASA Ⅵ干预还显著提高了睡眠剥夺小鼠海马中的p-PI3K、PI3K、Akt蛋白表达水平及新生神经元数量(P<0.05)。PI3K/Akt抑制剂LY294002处理显著降低ASA Ⅵ的干预效果。结果表明,ASA Ⅵ可改善睡眠剥夺小鼠学习记忆能力,其机制与PI3K/Akt信号通路激活相关。因此,作为抗炎、神经保护药物,ASA Ⅵ具有潜在的开发前景。     

戊四氮点燃癫痫大鼠空间学习记忆改变及海马突触素、突触后致密物PSD-95表达的变化

目的探讨戊四氮点燃癫痫对大鼠空间学习记忆的影响及可能的分子机制。方法戊四氮(pentylenetet-razol,PTZ)点燃建立慢性癫痫(chronic epileptic,CEP)模型,Morris水迷宫进行行为学检测,免疫组织化学方法观察大鼠海马CA1、CA3区突触素(synaptophysin,P38)和突触后致密物95(postsynaptic density 95,PSD-95)的表达,并用计算机图像分析系统对免疫反应结果进行处理。结果水迷宫试验检测癫痫组大鼠空间学习记忆能力受损;免疫组化结果表明其海马CA1、CA3区P38和PSD-95免疫反应产物较对照组明显减少(P<0.01,P<0.05)。结论戊四氮点燃癫痫大鼠伴有学习记忆功能减退,其海马神经元P38和PSD-95的表达减少可能参与了空间学习记忆受损。     

在不同形式的运动中，自噬可改善2型糖尿病小鼠认知功能障碍

2型糖尿病(T2DM)是一种代谢性疾病，易造成认知功能障碍。T2DM小鼠脑内自噬水平与认知功能下降有关。运动可以改善T2DM认知水平，但具体机制仍不清楚。本研究旨在探讨自噬在不同形式的运动干预改善T2DM小鼠认知功能障碍中的作用及分子机制。取雄性4周龄C57BL/6小鼠随机分成：对照组(C)、T2DM模型组(DM)、T2DM运动组和T2DM自噬抑制剂组。T2DM小鼠通过高脂饲养联合腹腔注射STZ造模。运动组采取跑台(T)、爬梯(R)、跑台联合爬梯(M);抑制剂组采用腹腔注射氯喹(CQ)(10 mg/kg),分为T2DM单纯抑制剂组(DM+CQ)、T2DM+CQ+跑台干预组(DM+T+CQ)。免疫荧光染色显示，3种运动干预均可降低T2DM小鼠海马组织Iba-1阳性细胞数量及荧光强度(P<0.05),降低小胶质细胞NLRP3荧光强度(P<0.05)。Western印迹结果显示，3种运动干预均可降低T2DM小鼠海马iNOS、GFAP、Iba-1蛋白质表达，增加Arg-1蛋白质表达，其中M组均有显著性差异(P<0.05);3种运动干预均可降低T2DM小鼠海马NLRP3复合物蛋...     

阿尔茨海默病血清miR-137、miR-138表达与认知功能损害和外周血淋巴细胞PI3K/Akt信号通路的关系研究

摘要 目的：探讨阿尔茨海默病（AD）患者血清微小核糖核酸（miR）-137、miR-138表达与认知功能损害和外周血淋巴细胞磷脂酰肌醇-3激酶/蛋白激酶（PI3K/Akt）信号通路的关系。方法：选取2020年1月至2022年5月青岛大学附属医院神经内科收治的95例AD患者（AD组）,根据临床痴呆评定量表（CDR）评分将患者分为轻度组（1分,35例）、中度组（2分,42例）、重度组（3分,18例）,另选取63例体检健康志愿者为对照组。检测AD组、对照组血清miR-137、miR-138表达水平以及外周血淋巴细胞PI3K/Akt信号通路相关蛋白表达,采用简易智能精神状态检查量表（MMSE）、蒙特利尔认知评估量表（MoCA）评估认知功能。分析血清miR-137、miR-138与MMSE、MoCA评分以及外周血淋巴细胞PI3K、Akt、B淋巴细胞瘤-2基因（Bcl-2）、Bcl-2相关X蛋白基因（Bax）表达的相关性。结果：AD组血清miR-137水平、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达水平及MMSE、MoCA评分低于对照组（P＜0.05）,血清miR-138、外周血淋巴细胞Bax蛋白表达水平高于对照组（P＜0.05）。重度组血清miR-137水平、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达水平及MMSE、MoCA评分低于中度组和轻度组（P＜0.05）,且中度组低于轻度组（P＜0.05）;重度组血清miR-138、外周血淋巴细胞Bax蛋白表达水平高于中度组和轻度组（P＜0.05）,且中度组高于轻度组（P＜0.05）。AD患者血清miR-137水平与MMSE、MoCA评分、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达呈正相关（P＜0.05）,与外周血淋巴细胞Bax蛋白表达呈负相关（P＜0.05）;AD患者血清miR-138水平与MMSE、MoCA评分、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达呈负相关（P＜0.05）,与外周血淋巴细胞Bax蛋白表达呈正相关（P＜0.05）。结论：AD患者的血清miR-137表达水平降低、miR-138表达水平增高,与认知功能障碍有关,且miR-137、miR-138可能通过调控PI3K/Akt信号通路参与AD发病过程。     

紫丁香苷调控PI3K/Akt/mTOR信号通路诱导乳腺癌细胞凋亡的研究

目的 研究紫丁香苷的抗乳腺癌作用及分子机制，为紫丁香苷的临床应用提供理论依据。方法 MTT检测紫丁香苷对乳腺癌细胞增殖的抑制作用；台盼蓝、TUNEL和Annexin V-FITC/PI染色检测细胞的凋亡状况，Western bolt检测Caspase-3的活化情况，判断细胞凋亡是否发生；检测凋亡相关蛋白B淋巴细胞瘤2（Bcl-2）的表达，结合JC-1染色探讨紫丁香苷对线粒体凋亡途径的影响；运用PI3K激动剂Recilisib做对比，qRT-PCR和Western bolt检测紫丁香苷调控PI3K/Akt/mTOR通路诱导癌细胞凋亡的作用。结果 紫丁香苷对乳腺癌细胞的增殖具有时间和剂量依赖的抑制作用，能诱导癌细胞发生凋亡。进一步研究发现，紫丁香苷处理后，细胞内Caspase-3被激活，Bcl-2表达下降，线粒体膜电位明显丧失，PI3K、Akt和mTOR的mRNA与蛋白质水平表达无明显变化，但蛋白质磷酸化水平明显下降；Recilisib处理后部分抵消了紫丁香苷对乳腺癌细胞凋亡的作用。结论 紫丁香苷对乳腺癌细胞MDA-MB-231和MCF-7具有良好的抑制作用，其通过抑制PI3K/Akt/mTOR信号通路的活化来抑制细胞增殖并诱导细胞发生线粒体途径的凋亡。紫丁香苷是具有开发潜力的抗乳腺癌药物。     

消痰化瘀利窍方对慢性间歇性低氧小鼠认知障碍的改善作用*

目的: 探讨消痰化瘀利窍方对慢性间歇性低氧小鼠认知障碍的改善作用。方法: 48只雄性C57小鼠随机分为4组(n=12),常氧对照组(Normoxia),慢性间歇性低氧组(CIH)、慢性间歇性低氧中药干预组(Formula+CIH)、中药对照组(Formula)。Normoxia和Formula组暴露于常氧环境,CIH与Formula+CIH组暴露于间歇性低氧环境(低氧舱中前1.5 min充入氮气使舱内氧浓度降至9%,后1.5 min充入氧气使氧浓度恢复至21%,3 min/循环,每天上舱8 h,共35 d)。其中,Formula +CIH与Formula组于每日灌胃中药水煎液灌胃(26.8 g/kg),同时CIH组与Normoxia组灌胃给予同体积生理盐水。实验在26～35 d连续应用水迷宫观测各组小鼠的学习和记忆能力,35 d造模结束后,首先进行Y-迷宫实验,麻醉后断头取脑,分离海马组织。应用尼氏染色和电镜观察海马神经元的形态学改变,通过Western blot检测海马神经元synapsin和PSD-95的表达水平。结果: 与Normoxia组相比,CIH组小鼠水迷宫和Y-迷宫的成绩显著下降(P＜0.01,P＜0.01),海马神经元尼氏小体的数量和突触后致密物质的厚度均减少,PSD-95蛋白表达下调(P＜0.01),而synapsin表达无明显改变。与CIH组小鼠比较,消痰化瘀利窍方干预可显著提高小鼠水迷宫和Y-迷宫的成绩(P＜0.01),增加海马神经元尼氏小体的数量和突触后致密物质的厚度,上调PSD-95蛋白表达水平(P＜0.01)。结论: 消痰化瘀利窍方可改善由CIH诱导的突触后致密区的结构和功能受损,进而对认知功能障碍起到保护作用。     

Sex differences and synchronous development of steroid receptor coactivator-1 and synaptic proteins in the hippocampus of postnatal female and male C57BL/6 mice

The structure and function including synaptic plasticity of the hippocampus are deeply affected by steroids in a sex-dependant manner, these processes are believed to be mediated by steroid receptors though their coactivators. Our previous studies have reported the developmental profiles of steroid receptor coactivator-1 (SRC-1) and PSD-95 in the hippocampus of postnatal female rats and the sex-differences of SRC-1 immunoreactivities in the brain of adult mice. However, whether there are any sex differences about postnatal development of SRC-1 and synaptic proteins in the hippocampus remain unclear. In this study, we investigated the postnatal profile of SRC-1 and key synaptic protein synaptophysin (SYN), PSD-95 and GluR1 in the hippocampus of female and male mice using immunohistochemistry and Western blot. The results showed that in the female hippocampus, the highest levels of SRC-1 were detected at P14, SYN and GluR1 at P30 and PSD-95 at P60; while in the males, the highest levels of SRC-1, SYN and GluR1 were detected at P30, and PSD-95 at P60. Female hippocampus tended to have higher levels of SRC-1, SYN and GluR1 before P30 and PSD-95 before P14; while male hippocampus have higher levels of PSD-95 at P14, P60 and GluR1 at P0. Correlation analysis showed the profiles of SRC-1 were highly correlated with each synaptic protein. The above results showed that in the hippocampus, except some minor sex differences detected at some time-point examined, females and males shared similar postnatal developmental profile and SRC-1 may be deeply involved in the regulation of hippocampal synaptogenesis.     

基于PI3K/PTEN/AKT信号途径探讨褪黑素对脊髓损伤大鼠突触可塑性的影响

目的:探讨褪黑素对脊髓损伤大鼠突触可塑性的影响及磷脂酰肌醇3-激酶/张力蛋白同源基因/蛋白激酶B(PI3K/PTEN/AKT)信号途径在其中的作用。方法:选择4月龄SPF级雄性SD大鼠48只,将其随机分为对照组(CON)、模型组(SCI)、褪黑素组(MT)和褪黑素受体拮抗剂组(LUZ),每组12只大鼠。对照组大鼠背部切口后缝合,余下各组大鼠使用改良的Allen's法建立T9水平的脊髓损伤模型。模型建立后,褪黑素组及褪黑素受体拮抗剂组每天腹腔注射褪黑素及褪黑素抑制剂,剂量为12.5 mg·kg~(-1)·d~(-1),对照组和模型组每天注射同体积的生理盐水。治疗后第3、7、14、21、28天进行BBB评分,实验结束处死大鼠取胸椎8-10节段脊髓组织,分别采用免疫组化方法测尼氏小体数量及Western Blot检测PTEN、Synapsin、PSD-95、Gap-43、Akt蛋白的表达。结果:与SCI模型大鼠相比,MT给药干预14 d后的SCI大鼠BBB评分及痛觉压力值均明显降低(P0.05),尼氏小体灰度值提高(P 0.05),PTEN、Synapsin、PSD-95、Gap-43、Akt蛋白的表达均显著上调(P 0.05)。结论:MT可能通过激活PI3K/PTEN/Akt信号途径,上调突触可塑性相关蛋白的表达,促进SCI大鼠突触修复。     

Influence of circadian disorder on structures and functions of neurons in hippocampus of mice

Objective: This study explored the effect of circadian disorder on structure and function of neurons in hippocampus of mice. Methods: Forty male ICR mice were randomly divided into rhythm disorder group (RDG) and normal rhythm group (NRG). The RDG was treated with 3 h light/5 h dark and 5 h light/3 h dark light–dark (LD) cycle alternately. The normal rhythm group was treated with 12/12 h LD cycle. Electron microscope was used to detect the mouse hippocampal cell ultrastructure. Morris water maze was used to test mice cognitive function. The brain slice electric physiological techniques were used to detect synapses in the hippocampal Long-term potentiation (LTP) effect. Results: The time of through central area of RDG was less than that of NRG. The axoplasm in anterior-posterior membranes of synapses of RDG was dissolved and synaptic vesicles of RDG were decreased. Conclusion: Circadian rhythm disorder induced by irregular light–dark circle can lead to the structural damage of hippocampal neurons and damage the cognitive function in mice.     

APP5肽对糖尿病小鼠学习记忆功能与海马神经元蛋白表达的影响

目的研究APP5肽对糖尿病模型小鼠学习记忆能力及海马神经元蛋白表达的影响。方法用链脲佐菌素诱发小鼠糖尿病模型,应用APP5肽（0.0014 mg/kg）皮下注射治疗,5周后进行Morris水迷宫试验;小鼠脑组织海马做Akt、PI3K、P-CREB、Bcl-2、Bax、CytoC免疫组织化学染色;另一部分鼠脑海马,做Bcl-2、Bax抗体蛋白免疫印记。结果（1）水迷宫试验：糖尿病模型小鼠到达站台游动时间比正常对照组延长（P〈0.01）;而APP5肽皮下注射治疗组较DM组动物分别缩短（P〈0.01）。（2）神经免疫组织化学实验和Western blot：给予APP5肽糖尿病小鼠与对照组小鼠海马组织内神经元表达细胞存活相关蛋白及抗凋亡相关蛋白PI3K、Akt、P-CREB、Bcl-2阳性细胞数相似,明显高于糖尿病小鼠（P〈0.01）;APP5肽给予糖尿病小鼠与对照组小鼠表达凋亡蛋白Bax、cytoC阳性细胞数相似,明显少于糖尿病小鼠（P〈0.01）。Western blot结果相同。结论糖尿病小鼠海马神经元表达细胞存活相关蛋白下降,神经元表达细胞凋亡相关蛋白增加,导致其学习记忆能力下降。APP5肽应用可以使上述蛋白恢复到接近正常,从而改善糖尿病小鼠学习记忆能力。     

Altered synaptic marker abundance in the hippocampal stratum oriens of Ts65Dn mice is associated with exuberant expression of versican

DS (Down syndrome), resulting from trisomy of chromosome 21, is the most common cause of genetic mental retardation; however, the molecular mechanisms underlying the cognitive deficits are poorly understood. Growing data indicate that changes in abundance or type of CSPGs (chondroitin sulfate proteoglycans) in the ECM (extracellular matrix) can influence synaptic structure and plasticity. The purpose of this study was to identify changes in synaptic structure in the hippocampus in a model of DS, the Ts65Dn mouse, and to determine the relationship to proteoglycan abundance and/or cleavage and cognitive disability. We measured synaptic proteins by ELISA and changes in lectican expression and processing in the hippocampus of young and old Ts65Dn mice and LMCs (littermate controls). In young (5 months old) Ts65Dn hippocampal extracts, we found a significant increase in the postsynaptic protein PSD-95 (postsynaptic density 95) compared with LMCs. In aged (20 months old) Ts65Dn hippocampus, this increase was localized to hippocampal stratum oriens extracts compared with LMCs. Aged Ts65Dn mice exhibited impaired hippocampal-dependent spatial learning and memory in the RAWM (radial-arm water maze) and a marked increase in levels of the lectican versican V2 in stratum oriens that correlated with the number of errors made in the final RAWM block. Ts65Dn stratum oriens PNNs (perineuronal nets), an extension of the ECM enveloping mostly inhibitory interneurons, were dispersed over a larger area compared with LMC mice. Taken together, these data suggest a possible association with alterations in the ECM and inhibitory neurotransmission in the Ts65Dn hippocampus which could contribute to cognitive deficits.     

Dynorphin activation of kappa opioid receptor protects against epilepsy and seizure-induced brain injury via PI3K/Akt/Nrf2/HO-1 pathway

Dynorphins act as endogenous anticonvulsants via activation of kappa opioid receptor (KOR). However, the mechanism underlying the anticonvulsant role remains elusive. This study aims to investigate whether the potential protection of KOR activation by dynorphin against epilepsy was associated with the regulation of PI3K/Akt/Nrf2/HO-1 pathway. Here, a pilocarpine-induced rat model of epilepsy and Mg²⁺-free-induced epileptiform hippocampal neurons were established. Decreased prodynorphin (PDYN) expression, suppressed PI3K/Akt pathway, and activated Nrf2/HO-1 pathway were observed in rat epileptiform hippocampal tissues and in vitro neurons. Furthermore, dynorphin activation of KOR alleviated in vitro seizure-like neuron injury via activation of PI3K/Akt/Nrf2/HO-1 pathway. Further in vivo investigation revealed that PDYN overexpression by intra-hippocampus injection of PDYN-overexpressing lentiviruses decreased hippocampal neuronal apoptosis and serum levels of inflammatory cytokines and malondialdehyde (MDA) content, and increased serum superoxide dismutase (SOD) level, in pilocarpine-induced epileptic rats. The protection of PDYN in vivo was associated with the activation of PI3K/Akt/Nrf2/HO-1 pathway. In conclusion, dynorphin activation of KOR protects against epilepsy and seizure-induced brain injury, which is associated with activation of the PI3K/Akt/Nrf2/HO-1 pathway.     

Rosmarinic acid and ursolic acid alleviate deficits in cognition,synaptic regulation and adult hippocampal neurogenesis in an Aβ1-42-induced mouse model of Alzheimer's disease

BackgroundRosmarinus officinalis, commonly known as rosemary, is a medicinal herb that presents significant biological properties such as antimicrobial, antioxidant, anti-inflammatory, anti-diabetic and anti-depressant activities. Recent findings correlate impaired adult neurogenesis, which is crucial for the maintenance of synaptic plasticity and hippocampal functioning, synaptic regulation with the pathological hallmarks of Alzheimer's disease (AD). These observations call for the need to developing compounds that promote neurogenesis and alleviates deficits in cognition and synaptic regulation.Purpose and study designThe present study was conducted to determine the proneurogenic effects of R. officinalis and its active compounds (ursolic acid and rosmarinic acid) in comparison to Donepezil in an Aβ_1-42-induced mouse model of AD.MethodsBALB/c mice were divided into ten groups. Half were injected with Aβ_1-42 in the hippocampus through stereotaxic surgery to generate the disease groups. The other half received control injections. Each set of five groups were administered orally with vehicle, an ethanolic extract of R. officinalis, ursolic acid, rosmarinic acid or donepezil. Behavior analysis included the Morris water maze test, the novel object recognition test and the Elevated plus maze. The mice were then sacrificed and the hippocampal tissue was processed for immunohistochemistry and gene expression analysis.ResultsThe results show a protective effect by rosmarinic acid and ursolic acid in reversing the deficits in spatial and recognition memory as well as changes in anxiety induced by Aβ_1-42. The neuronal density and the expression levels of neurogenic (Ki67, NeuN and DCX) and synaptic (Syn I, II, III, Synaptophysin and PSD-95) markers were also normalized upon treatment with rosmarinic and ursolic acid.ConclusionOur findings indicate the potential of R. officinalis and its active compounds as therapeutic agents against Aβ_1-42-induced neurotoxicity in AD.