基于突触可塑性探讨电针改善大脑中动脉闭塞大鼠运动障碍的作用机制

目的：基于突触可塑性观察电针曲池、足三里对大脑中动脉闭塞（MCAO）大鼠运动障碍的改善。方法：将60只雄性SD大鼠随机分为假手术组、模型组、穴位组、非穴组，每组15只。采用Zea Longa线拴法制备MCAO大鼠模型，电针曲池、足三里，干预14 d。通过神经功能评分判断大鼠的神经功能缺损情况；CatWalk步态分析比较各组大鼠运动功能，TTC染色观察脑梗死体积，透射电镜观察突触超微结构和数量，免疫荧光检测缺血侧运动皮层突触相关因子突触后致密物-95（PSD-95)、突触蛋白的表达情况。结果：干预14 d后，与模型组比较，穴位组大鼠神经功能评分降低(P<0.05)；步行速度提高、双足支撑时间缩短(P<0.05)；脑梗死体积减少(P<0.05)；突触超微结构改善明显，突触数量增加(P<0.05)，突触相关因子突触蛋白、PSD-95表达上调(P<0.05)。Catwalk步态参数、脑梗死体积与突触超微结构改善有一致性。结论：电针曲池、足三里穴可改善MCAO大鼠运动障碍，其机制可能与上调突触相关因子的表达，改善突触可塑性有关。     

Intranasal Dexamethasone Reduces Mortality and Brain Damage in a Mouse Experimental Ischemic Stroke Model

Neuroinflammation triggered by the expression of damaged-associated molecular patterns released from dying cells plays a critical role in the pathogenesis of ischemic stroke. However, the benefits from the control of neuroinflammation in the clinical outcome have not been established. In this study, the effectiveness of intranasal, a highly efficient route to reach the central nervous system, and intraperitoneal dexamethasone administration in the treatment of neuroinflammation was evaluated in a 60-min middle cerebral artery occlusion (MCAO) model in C57BL/6 male mice. We performed a side-by-side comparison using intranasal versus intraperitoneal dexamethasone, a timecourse including immediate (0 h) or 4 or 12 h poststroke intranasal administration, as well as 4 intranasal doses of dexamethasone beginning 12 h after the MCAO versus a single dose at 12 h to identify the most effective conditions to treat neuroinflammation in MCAO mice. The best results were obtained 12 h after MCAO and when mice received a single dose of dexamethasone (0.25 mg/kg) intranasally. This treatment significantly reduced mortality, neurological deficits, infarct volume size, blood–brain barrier permeability in the somatosensory cortex, inflammatory cell infiltration, and glial activation. Our results demonstrate that a single low dose of intranasal dexamethasone has neuroprotective therapeutic effects in the MCAO model, showing a better clinical outcome than the intraperitoneal administration. Based on these results, we propose a new therapeutic approach for the treatment of the damage process that accompanies ischemic stroke.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00884-9) contains supplementary material, which is available to authorized users.     

补阳还五汤对缺血性脑卒中大鼠神经元自噬的保护作用及机制分析

目的探究补阳还五汤中药对大脑中动脉闭塞(MCAO)大鼠再灌注24 h后抗神经元缺血损伤的治疗效果,并分析其改善神经元自噬相关的可能作用机制。方法采用MCAO法对成年雄性SD大鼠进行大脑中动脉闭塞处理2 h,再灌注24 h后成模,分为假手术组、模型组和治疗组。模型组和治疗组大鼠在MCAO造模手术后进行24 h再灌注,治疗组腹腔注射补阳还五汤方剂,模型组和假手术组大鼠均腹腔注射接受等体积的生理盐水,共计14 d。再灌注损伤后1 d、7 d、14 d进行神经系统损伤严重程度(NSS)评分;第14天进行平衡木行走试验;采用苏木精-伊红染色法测定大脑梗死体积;采用免疫组化分析皮质缺血区存活神经元密度;采用免疫印迹法对自噬相关蛋白表达水平(Beclin1,LC3)和线粒体动力学蛋白水平(Parkin,DRP1,OPA1)。结果与假手术组比较,模型组在MACO术后1 d、7 d、14 d NSS评分显著升高;第7天模型组和治疗组间NSS评分无显著差异(P> 0. 05),第14天时治疗组大鼠NSS评分显著低于同时间点的模型组大鼠评分(P <0. 01)。与假手术组相比,模型组大鼠通过平衡木的时间均显著延长(P <0. 01);而与模型组相比,治疗组大鼠通过平衡木的时间显著缩短(P <0. 01)。第14天后,与假手术组相比,模型组大鼠脑梗死面积百分比显著升高,缺血皮质缺血区神经元密度显著下降(P <0. 01);与模型组比较,治疗组大鼠脑梗死面积百分比显著降低,皮质区神经元丢失程度显著缓解(P <0. 01)。与假手术组相比,模型组大鼠皮质区Beclin1、LC3-II、Parkin、DRP1和OPA1水平显著均下降(P <0. 001),而与模型组相比,治疗组皮质区Beclin1、LC3-II、Parkin、DRP1和OPA1蛋白表达下降程度显著缓解(P <0. 01)。结论补阳还五汤通过调节大鼠脑卒中后皮质缺血区域自噬,稳定线粒体功能,发挥神经保护作用。     

参附注射液作用机制的计算机系统生物学分析

目的:参附注射液是传统中药红参与附子的复方制剂,临床主适应症为充血性心力衰竭、缺血性脑卒中等。以缺血性脑卒中为导向,采用系统生物学和实验研究方法,对参附注射液调节生物学网络的分子机制做一阐释。方法:以参附注射液的28个成分出发,分别从TCMGene DIT数据库系统和Agilent literature search系统中挖掘参附注射液中成分作用的蛋白质数据,并辅助以Pharmmapper反向对接靶标,构建参附注射液多成分-蛋白网络,在Genecards,BIND,Bio GRID,Int Act,Mint等数据库中挖掘蛋白之间关联,建立蛋白相互作用网络。提取显著性差异蛋白子网络一个,并对其中通路以Western blot蛋白印迹方法加以验证。结果:参附注射液成分与55个蛋白有连接,构成53个无孤立结点的蛋白相互作用网络。应用Cluster One模块对蛋白相互作用网络富集分析,提取显著性差异P0.05的子网络1个,子网络中含有关键蛋白15个,经Biocart信号通路映射,涉及NF-κB信号通路,AKT信号通路,Toll样受体信号通路,MAPK信号通路等。采取Western blot方法对富集指数P值最小的NF-κB信号通路进行验证,发现参附注射液在缺血1 h再灌注24 h的MCAO模型上对NF-κB p65和IκB-α的磷酸化表达有明显下调作用。结论:采用计算机系统生物学和实验验证方式初步阐释了参附注射液主要化合物防治疾病的分子机制,并以分子生物学实验方式对所预测的信号通路进行验证,为中药复方的系统研究提供参考。     

麝香醒脑滴丸对脑缺血再灌注损伤的保护作用

目的：探讨麝香醒脑滴丸（Shexiang Xingnao dropping pills,SXD）对大鼠脑缺血再灌注损伤的保护作用及其机制。方法线栓法建立大鼠局灶性脑缺血（MCAO）再灌注模型,按 Bederson 的方法对 MCAO 再灌注0、4、8、22 h 时大鼠的神经功能损伤进行评分;测定脑梗死百分比、脑指数、脑含水量;检测血浆中血小板聚集率和脑组织超氧化物歧化酶（SOD）、乳酸脱氢酶（LDH）活性以及丙二醛（MDA）含量;HE 染色观察脑组织病理变化。结果与模型组比较,SXD（0．42、0．84 g·kg －1）对MCAO 再灌注大鼠的神经功能损伤评分有一定的改善作用,能减少脑梗死百分比、脑含水量、脑指数和血小板聚集率,提高脑组织 SOD 和 LDH 活性,降低脑组织中 MDA 含量,减轻脑组织皮质神经元的损伤。结论SXD 对脑缺血再灌注损伤具有一定的保护作用,其机制可能与抗氧自由基损伤及抑制血小板聚集等有关。     

大鼠大脑中动脉缺血再灌注后不同时间点梗死体积的变化

目的:在局灶缺血模型中,研究再灌注后0 h、6 h、24 h、48 h、72 h对大鼠梗死灶体积的影响。方法:将大鼠分为假手术组(sham组)和实验组,实验组在激光多普勒血流仪的监测下进行手术,术后有3分症状的入主,然后随机分为0 h组、6 h组、24 h组、48 h组、72 h组。在不同的时间点处死大鼠,行TTC染色,然后计算梗死体积。结果:再灌注24 h之前,随着再灌注时间的延长梗死体积逐渐增大,0～24 h,梗死体积变化有显著性差异;但再灌注24 h之后,梗死体积不再发生实质性的增加,24～72 h,梗死体积无显著性差异。结论:在研究局灶脑缺血梗死体积的实验中,24 h是一个非常重要的时间点。     

Relative neuroprotective effects hyperbaric oxygen treatment and TLR4 knockout in a mouse model of temporary middle cerebral artery occlusion

Purpose: To examine the effects of hyperbaric oxygen (HBO) therapy and knockout of toll-like receptor 4 (TLR4) on the outcome of temporary middle cerebral artery occlusion (MCAO) in a mouse model. Materials and Methods: MCAO was induced in anesthetized male C57Bl/6 mice (WT) and TLR4 knockout mice (TLR4^?/?) using an intra-arterial filament method. After 30 or 90 min, the filament was removed, and the mice were given either no treatment (WT and TLR4^?/- groups) or HBO (WT only). Mice were euthanized 24 h after MCAO, and the brain infarct area was examined using 2,3,5-triphenyltetrazolium chloride (TTC) staining. Results: In the WT group, without treatment, lesion volume was 120 ± 13 mm³ in the mice subjected to 30 min’ MCAO and 173 ± 23 mm³ in the mice subjected to 90 min’ MCAO. Respective values with HBO treatment were 66.5 ± 36.7 mm³ and 53.2 ± 17.2 mm³. The difference was significant only for 90-minute MCAO (p < 0.01, nonparametric test). In the TLR4^?/? group (all untreated), lesion volume was 95.9 ± 17.9 after 90 min of MCAO, which was significantly lower than in the untreated WT animals (p < 0.05, nonparametric test). Conclusions: A single treatment of HBO immediately after MCAO followed by 24 h’ reperfusion significantly reduces edema and may improve perfusion. TLR4 knockout protects mice from MCAO damage, but to a lesser extent than HBO treatment.     

强迫性上肢训练对缺血性脑卒中大鼠神经传导束的影响

目的探讨强制性功能训练对大鼠模型的神经传导束的影响。方法55只雌性SD大鼠随机分成两组：模型自然恢复（NR）组和模型强制训练（CIMT）组。CIMT组每天束缚健侧上肢强制进行滚筒、平衡木、网屏训练;NR组放在相同的自然环境下饲养。CIMT组在术后5d、10d、15d、30d、60d分别训练,行为学评分。最后的时间点各取5只大鼠,分别行核磁共振扫描,取大脑脚和脊髓进行髓鞘染色进行光镜观察。结果CIMT组的平衡能力、协调能力和患侧上肢的肌力较NR组恢复快（P〈0.05）。CI-MT组患侧大脑脚和脊髓的神经纤维明显增粗,较少脱髓鞘,细胞数也略增多。结论CIMT训练可以最大限度地募集患侧存在功能的神经纤维（神经传导束）,降低其脱髓鞘的神经传导束的数目。     

局灶性脑缺血预处理上调大鼠梗死区周围巢蛋白的表达

目的观察局灶性脑缺血预处理(IP)对巢蛋白(NESTIN)表达的影响,探讨NESTIN与脑缺血耐受(BIT)的关系及可能的内源性神经保护机制。方法 45只SD雄性大鼠随机分为脑缺血预处理(CIP)组、大脑中动脉阻塞(MCAO)组、假手术(sham)组。采用TTC染色测定脑梗死体积,光镜下观察脑组织病理改变,免疫组织化学染色和图像分析评价各组NESTIN的表达。结果再灌注24及72 h,CIP组脑梗死体积比分别为12.4%±3.2%、9.8%±1.9%,较MCAO组的18.5%±3.7%、15.8%±3.5%明显减小(P<0.05),免疫组化NESTIN阳性细胞数及Western blot测定缺血侧脑组织的NESTIN蛋白表达水平,均高于同时间段的MCAO组(P<0.05)。结论 CIP可有效减小局灶性脑缺血再灌注后的脑梗死体积,并促进梗死区周围脑组织表达敏感的胚性蛋白NESTIN,后者可能与BIT的脑保护机制有关。     

Antagonists of the Vasopressin V1 Receptor and of the β1-Adrenoceptor Inhibit Cytotoxic Brain Edema in Stroke by Effects on Astrocytes – but the Mechanisms Differ

Brain edema is a serious complication in ischemic stroke because even relatively small changes in brain volume can compromise cerebral blood flow or result in compression of vital brain structures on account of the fixed volume of the rigid skull. Literature data indicate that administration of either antagonists of the V1 vasopressin (AVP) receptor or the β₁-adrenergic receptor are able to reduce edema or infarct size when administered after the onset of ischemia, a key advantage for possible clinical use. The present review discusses possible mechanisms, focusing on the role of NKCC1, an astrocytic cotransporter of Na⁺, K⁺, 2Cl^- and water and its activation by highly increased extracellular K⁺ concentrations in the development of cytotoxic cell swelling. However, it also mentions that due to a 3/2 ratio between Na⁺ release and K⁺ uptake by the Na⁺,K⁺-ATPase driving NKCC1 brain extracellular fluid can become hypertonic, which may facilitate water entry across the blood-brain barrier, essential for development of edema. It shows that brain edema does not develop until during reperfusion, which can be explained by lack of metabolic energy during ischemia. V1 antagonists are likely to protect against cytotoxic edema formation by inhibiting AVP enhancement of NKCC1-mediated uptake of ions and water, whereas β₁-adrenergic antagonists prevent edema formation because β₁-adrenergic stimulation alone is responsible for stimulation of the Na⁺,K⁺-ATPase driving NKCC1, first and foremost due to decrease in extracellular Ca²⁺ concentration. Inhibition of NKCC1 also has adverse effects, e.g. on memory and the treatment should probably be of shortest possible duration.