Systems Neuroprotective Mechanisms in Ischemic Stroke

Ischemic stroke, although causing brain infarction and neurological deficits, can activate innate neuroprotective mechanisms, including regional mechanisms within the ischemic brain and distant mechanisms from non-ischemic organs such as the liver, spleen, and pancreas, supporting neuronal survival, confining brain infarction, and alleviating neurological deficits. Both regional and distant mechanisms are defined as systems neuroprotective mechanisms. The regional neuroprotective mechanisms involve release and activation of neuroprotective factors such as adenosine and bradykinin, inflammatory responses, expression of growth factors such as nerve growth factors and neurotrophins, and activation and differentiation of resident neural stem cells to neurons and glial cells. The distant neuroprotective mechanisms are implemented by expression and release of endocrine neuroprotective factors such as fibroblast growth factor 21, resistin like molecule γ, and trefoil factor 3 from the liver; brain-derived neurotrophic factor and nerve growth factor from the spleen; and neurotrophin 3 and vascular endothelial growth factor C from the pancreas. Furthermore, ischemic stroke induces mobilization of bone marrow hematopoietic stem cells and endothelial progenitor cells into the circulatory system and brain, contributing to neuroprotection. The regional and distant mechanisms may act in coordination and synergy to protect the ischemic brain from injury and death. This paper addresses these mechanisms and associated signaling networks.     

应用手持激光器建立光化学法脑梗死动物模型

目的应用手持激光器作为光源建立光化学法局灶性脑梗死动物模型。方法将36只SD大鼠随机分为4组,即A组：开骨窗至硬脑膜,不注射玫瑰红,手持激光器照射5rain;B组：开骨窗至硬脑膜,注射玫瑰红,手持激光器照射5min;C组：保留颅骨内板,注射玫瑰红,手持激光器照射5min;D组：开骨窗至硬脑膜,注射玫瑰红,冷光源照射40rain。于术后24、48h对各组大鼠进行神经功能的行为学评分,进行MR扫描,术后48h处死动物,TTC染色测量梗死体积,光镜下观察病理改变,比较各组的模型制作成功率。结果不同方法进行动物模型制作时,24h神经功能的行为学评分有显著性差异,48h后差异消失。头部MR扫描显示,A组未见脑梗死形成,B组、c组全部有脑梗死灶形成,D组仅部分大鼠形成梗死灶,但体积明显较B、C组小,另外C组有2例合并硬膜外血肿。TTC染色A组未见梗死灶形成,B组、C组可见恒定的梗死灶,D组仅部分形成梗死灶。B、C、D组模型制作成功率分别为100％、80％、50％,将B组、C组合并为手持激光器组,与冷光源组（D组）比较,两种方法间有显著性差异（P=0．026）。结论应用手持激光器作为照射光源与冷光源相比,有更高的模型制作成功率。     

缺血性脑卒中二级预防研究进展

脑卒中具有发病率高、致残率高、复发率高、病死率高、治疗效果差的"四高一低"特点,是一种严重危害人类健康的全球性问题,被称为人类健康的第一号杀手!随着医学的进步,卒中死亡率下降,卒中复发率随之增加。然而,脑卒中是可预防性疾病,有效地预防措施不仅可以降低脑卒中的复发率,而且能降低与脑卒中有关的医疗费用,减轻家庭与社会的经济负担,因此,脑卒中的预防已成为世界各国研究的热点和焦点。本文就脑卒中二级预防做一综述。     

Influence of temperature on ischemic brain: basic and clinical principles

In the last decades, the interest in the association between body temperature and stroke outcome has reemerged, and the use of animal models has made it possible to know the underlying pathogenic mechanisms involved, most of them with pending confirmation in human clinics. In this work, we will review the effects of hyperthermia and hypothermia and its pathogenesis on ischemic stroke, and the evidence of the efficacy and safety of anti-hyperthermic and hypothermic treatments. We will describe how treatment of hyperthermia on ischemic stroke patients, improves patient comfort and outcome, both in the short and the long term, but new clinical studies are needed in this field. Despite the theoretical and experimental bases in favor of hypothermia for the treatment of brain ischemia, there is no definitive clinical evidence that has proved its benefits, so far. With current knowledge, an objective of a body temperature between 35.5 and 36.5 °C seems an optimal therapeutic target for both hyperthermic and normothermic patients.     

The Neuroprotective Effects of Coccomyxa Gloeobotrydiformis on the Ischemic Stroke in a Rat Model

Stroke is a major cause of mortality and the leading cause of permanent disability. In this study, we adopted the classic middle cerebral artery occlusion(MCAO) stroke model to observe the therapeutic effects of coccomyxa gloeobotrydiformis(CGD) on ischemic stroke, and discuss the underlying mechanisms. Low dose (50 mg/kg.day) and high dose (100 mg/kg.day) concentrations of the drug CGD were intragastrically administrated separately for 8 weeks. Infarct volumes, neurologic deficits and degree of stroke-induced brain edema were measured 24 hours after reperfusion. Furthermore, oxidative stress related factors (SOD and MDA), mitochondrial membrane potential, and apoptosis regulatory factors (mitochondrial Cyt-C, Bcl-2, Bax, and caspase-3) were all investigated in this research. We found that CGD attenuated cerebral infarction, brain edema and neurologic deficits; CGD maintained the mitochondrial membrane potential and decreased mitochondrial swelling. It also prevented oxidative damage by reducing MDA and increasing SOD. In addition, CGD could effectively attenuate apoptosis by restoring the level of mitochondrial Cyt C and regulating the expression of Bcl-2, Bax and caspase 3. These results revealed that CGD has a therapeutic effect on ischemic stroke, possibly by inducing mitochondrial protection and anti-apoptotic mechanisms.     

Neuroprotective Role of Astrocytic Gap Junctions in Ischemic Stroke

The role of astrocytic gap junctions in ischemia remains controversial. Several studies support that astrocytic gap junctions play a role in the spread of hypoxic injury, while other reports have demonstrated that blocking astrocytic gap junctions increases neuronal death. Using a stroke model on animals in which the astrocytic gap junction protein connexin43 (Cx43) was compromised, we explored the neuroprotective role of astrocytic gap junctions. A focal brain stroke was performed on heterozygous Cx43 null [Cx43(+/?)] mice, wild type [Cx43(+/+)] mice, astrocyte-directed Cx43 deficient [Cx43^{fl/ fl}/hGFAP-cre] mice (here designated as Cre(+) mice), and their corresponding controls [Cx43^fl/fl] (here designated as Cre(?) mice). Four days following stroke, ischemic lesions were measured for size and analyzed immunohistochemically. Stroke volume was significantly larger in Cx43(+/?) and Cre(+) mice compared to Cx43(+/+) and Cre(?) mice, respectively. Apoptosis as detected by TUNEL labeling and caspase-3 immunostaining was amplified in Cx43(+/?) and Cre(+) mice compared to their control groups. Furthermore, increased inflammation as characterized by the immunohistochemical staining of the microglial marker CD11b was observed in the Cre(+) mice penumbra. Astrocytic gap junctions may reduce apoptosis and inflammation in the penumbra following ischemic insult, suggesting that coupled astrocytes fulfill a neuroprotective role under ischemic stroke conditions.     

能量代谢信号通路对缺血性脑卒中神经保护作用的研究进展

据近几年研究发现,能量代谢通路中的关键酶,如AMPK、Sirt1、PGC-1α、NAMPT,在控制缺血再灌注引起的钙离子超载、兴奋性氨基酸毒性、过氧化应激等损伤途径中发挥重要的作用,并且对缺血性神经起到保护作用。分别介绍这些能量代谢通路中的关键蛋白在缺血性神经保护中的作用机制,旨在为缺血性脑卒中的治疗提供新思路。     

缺血性中风患者脑血管支架植入最佳时机的分析

目的:探讨缺血性中风患者脑血管支架植入的最佳时机。方法:选取我院收治的缺血性脑血管疾病患者90例,依据发病时间分为三组并进行脑血管支架植入术。对比三组患者治疗前后脑血管血流速度、认知功能评分及血管内皮细胞生长因子(VEGE)、碱性成纤维细胞生长因子(b FGF)、神经生长因子(NGF)的含量变化。结果:1三组患者手术后的脑血管血流速度与手术前相比明显改善,差异有统计学意义(P0.05),但三组之间比较无明显差异(P0.05);2三组患者手术后的认知功能均较手术前有所改善,与A组和C组比较,B组认知功能评分明显升高,差异有统计学意义(P0.05),而A组和C组比较无明显差异(P0.05);3三组患者手术后的血清VEGE、b FGF、NGF含量均较手术前升高,且B组明显高于A组和C组,差异有统计学意义(P0.05),而A组和C组间比较无明显差异(P0.05)。结论:脑血管支架植入时机与缺血性中风患者的临床疗效及预后可能有一定相关性,发病后1个月为脑血管支架植入最佳时机。     

铜纳米颗粒对缺血性卒中后神经血管单元的保护作用

目的:研究铜纳米颗粒(copper nanoparticle,Cu-nps)对缺血性卒中后神经血管单元(neurovascular units,NVU)的保护作用。方法:采用加热搅拌法合成Cu-nps。体内建立大鼠短暂大脑中动脉阻塞/再灌注模型(transient middle cerebral artery occlusion / reperfusion,tMCAO),实验分为正常组(sham)、模型组(tMCAO)、给药组(Cu-nps),检测各组脑梗死面积、神经凋亡情况、血脑屏障(blood-brain barrier,BBB)完整性以及相关蛋白表达。结果:制备出的Cu-nps以Cu²⁺、80 nm左右的粒径均匀存在,具有良好的生物相容性。Cu-nps靶向脑缺血部位受损神经元,提高神经元细胞活力,降低活性氧,减少神经元凋亡和脑梗死面积,降低伊文思蓝染料渗漏量和炎症因子表达。结论:Cu-nps可以减少氧化应激,保护BBB完整性,降低神经胶质细胞活化,保护NVU功能,从而降低脑缺血再灌注损伤。     

阿司匹林对骨髓间充质干细胞移植治疗缺血性脑卒中的影响研究进展

阿司匹林是缺血性脑卒中患者急性期治疗药物及卒中再发的二级预防常用药物,骨髓间充质干细胞(BMSCs)移植是治疗缺血性脑血管疾病的新的新兴技术。已证实阿司匹林可抑制骨髓间充质干细胞的增殖及影响骨髓间充质干细胞的分化。本文就阿司匹林对骨髓间充质干细胞移植治疗缺血性脑卒中的影响等进行综述。     

脑电仿生电刺激对缺血性脑卒中失眠症患者睡眠质量的影响

摘要 目的：探讨脑电仿生电刺激对缺血性脑卒中失眠症患者睡眠质量的影响。方法：2018年1月到2019年12月选择在新疆医科大学第六附属医院诊治的缺血性脑卒中失眠症患者120例,根据随机数字表法分为研究组与对照组各60例。对照组给予常规药物治疗,研究组在对照组治疗的基础上给予脑电仿生电刺激治疗,治疗观察4 w,评定患者睡眠质量变化情况。结果：两组治疗后的匹斯堡睡眠质量指数量表（Pittsburgh Sleep Quality Index,PSQI）评分都显著低于治疗前（P<0.05）,研究组评分也显著低于对照组（P<0.05）。治疗后研究组的总有效率为98.3 %,显著高于对照组的85.0 %（P<0.05）。研究组治疗后的左右椎动脉血流速度都显著高于治疗前（P<0.05）,也显著高于对照组（P<0.05）。治疗后两组的Berg平衡量表(Berg balance scale,BBS)与巴氏(Barthel)评分显著高于治疗前（P<0.05）,研究组评分也显著高于对照组（P<0.05）。结论：脑电仿生电刺激在缺血性脑卒中失眠症患者中的应用能改善睡眠质量,提高恢复平衡与日常生活功能,改善脑血流速度,从而提高治疗效果。     

急性缺血性脑卒中患者入院时血浆BNP水平与梗死部位关系

目的:分析急性缺血性脑卒中患者入院时血浆脑钠肽(BNP)水平与缺血性脑卒中梗死部位的关系。方法:随机入选88例急性缺血性脑卒中患者,按梗死部位,将其分为前循环病灶组(66名)和后循环病灶组(22名)两组进行比较。测定入院时血浆脑钠肽(BNP)水平进行比较。两组脑卒中病人的危险因素血糖、糖化血红蛋白、血脂全套,肝肾功能分析对比,并将急性缺血性脑卒中患者梗死部位相关的多个变量采用单因素logistic回归分析。结果:前循环病灶组血浆脑利钠肽水平的中位数是225.90 pg/mL,四分位数间距为596.00 pg/mL;后循环病灶组的中位数是750.95 pg/mL,四分位数间距为907.00 pg/mL。后循环病灶组血浆脑利钠肽水平要显著高于前循环病灶组血浆脑利钠肽水平,两个部位间入院时的脑利钠肽水平有统计学差异(P=0.004)。通过入院时脑利钠肽水平与缺血性脑卒中梗死部位的关系的ROC曲线,得出截点299.50 pg/mL。入院时血浆脑利钠肽水平≥299.50 pg/mL可以作为后循环病灶组的预测指标,其敏感性72.72%,特异性62.12%。结论:急性缺血性脑卒中患者入院时血浆BNP水平可作为急性期区别前后循环脑梗死的预测因子。     

Neuroprotective effect of aspirin combined with ginkgolide injection on cerebral ischemic stroke rats and its effect on ERK12 signal pathway

The main aim of this study was to evaluate the neuroprotective effect of aspirin combined with ginkgolide injection on cerebral ischemic stroke model rats and its effect on extracellular regulated protein kinase 1/2 (REK1/2) signaling pathway, and to clarify the possible mechanism of aspirin combined with ginkgolide injection on neuroprotective mechanism. Experimental rats were randomly divided into sham group, model group, aspirin group, ginkgolide group and combination group (aspirin + ginkgolide injection) (n = 20). The results revealed scores of neurological dysfunction and infarct volume in aspirin group, ginkgolide group and combination group rats were lower than those in model group (P < 0.05). Score of neurological dysfunction and the volume of cerebral infarction in combination group rats were lower than those in aspirin group and ginkgolide group (P < 0.05). Combination of aspirin and ginkgolide injection could better reduce brain water content, reduce apoptosis rate of cortical cells P < 0.05, reduce expression levels of caspase-3, Bax and p-REK1/2 proteins in ischemic brain tissue P < 0.05, and increase expression level of Bcl-2 protein than aspirin and ginkgolide injection alone P < 0.05). In conclusion, the synergistic neuroprotective effect of aspirin and ginkgolide injection on cerebral ischemic stroke rats is better than that of aspirin and ginkgolide injection alone. The mechanism of action may be that the two compounds can play a synergistic role and inhibit the activation of REK1/2 signaling pathway, thus inhibiting apoptosis of nerve cells and exerting neuroprotective effect.     

急性缺血性脑卒中患者入院时血浆BNP水平与梗死部位关系

目的：分析急性缺血性脑卒中患者入院时血浆脑钠肽（BNP）水平与缺血性脑卒中梗死部位的关系。方法：随机入选88例急性缺血性脑卒中患者,按梗死部位,将其分为前循环病灶组（66名）和后循环病灶组（22名）两组进行比较。测定入院时血浆脑钠肽（BNP）水平进行比较。两组脑卒中病人的危险因素血糖、糖化血红蛋白、血脂全套,肝肾功能分析对比,并将急性缺血性脑卒中患者梗死部位相关的多个变量采用单因素logistic回归分析。结果：前循环病灶组血浆脑利钠肽水平的中位数是225.90 pg/mL,四分位数间距为596.00 pg/mL;后循环病灶组的中位数是750.95 pg/mL,四分位数间距为907.00 pg/mL。后循环病灶组血浆脑利钠肽水平要显著高于前循环病灶组血浆脑利钠肽水平,两个部位间入院时的脑利钠肽水平有统计学差异（P=0.004）。通过入院时脑利钠肽水平与缺血性脑卒中梗死部位的关系的ROC曲线,得出截点299.50 pg/mL。入院时血浆脑利钠肽水平≥299.50 pg/mL可以作为后循环病灶组的预测指标,其敏感性72.72%,特异性62.12%。结论：急性缺血性脑卒中患者入院时血浆BNP水平可作为急性期区别前后循环脑梗死的预测因子。     

对比不同类型干细胞对于缺血性脑卒中治疗的研究进展

成人中枢神经系统存在着一定量的神经干细胞,其具有两大关键能力;自我更新和多向分化潜能。缺血性脑卒中是一种由于由脑血流的缺失或减少引起的脑动脉闭塞,进而导致脑组织梗死的脑血管疾病。虽然对于脑损伤的药物治疗已经取得了一定的成果,但目前以干细胞为基础的治疗方法仍成为了研究热点。无论是内源性神经干细胞还是外源性神经干细胞移植均可在脑损伤后向远端损伤区迁移并分化成新的神经细胞,从而在中枢神经系统疾病尤其是脑梗死后进行组织修复和功能恢复。因此在这篇综述中,我们主要探讨不同类型的干细胞对脑梗死介导的脑损伤的应用潜能,对比不同类型干细胞对缺血性脑卒中的治疗优缺点。     

氯吡格雷用于缺血性脑卒中的疗效评价及对血小板活性及血清炎症因子水平的影响

目的:评价氯吡格雷用于缺血性脑卒中的疗效及对血小板活性及血清炎症因子水平的影响。方法:选择我院2016年8月～2018年8月收治的150例缺血性脑卒中患者,按入院先后顺序分为对照组(83例)和研究组(67例)。对照组采用常规治疗,研究组在对照组基础上联合氯吡格雷治疗,比较两组的临床疗效,治疗前后血小板活性指标,血清超敏-C反应蛋白(hypersensitive c-reactive protein,hs-CRP)、白介素-6(Interleukin-6,IL-6)及肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)水平,美国国立卫生研究院卒中量表(National Institutes HealthStroke Scale,NIHSS)和日常生活活动能力(Activity of daily living,ADL)评分的变化和不良反应的发生情况。结果:治疗后,研究组总有效率显著高于对照组(91.04%vs. 78.31%,P0.05);两组血小板聚集率、血小板黏附率、P选择素、hs-CRP、IL-6、TNF-α及NIHSS评分均较治疗前明显下降,且研究组以上指标均显著低于对照组,两组ADL评分均较治疗前显著上升,且研究组明显高于对照组(P0.05)。两组治疗期间不良反应总发生率比较差异无统计学意义(P0.05)。结论:氯吡格雷用于缺血性脑卒中的效果明显优于常规治疗,其能够有效抑制血小板活性、降低炎症因子水平、改善患者神经功能和日常生活能力。     

GABA(A)-mediated toxicity of hippocampal neurons in vitro

In the present study, we examined whether the elevation of GABA by gamma-vinyl-GABA protects cultured rat fetal hippocampal neurons against toxicity induced by a 20-min incubation with 100 microM L-glutamate. Neither a 24-h pretreatment nor posttreatment with gamma-vinyl-GABA (100 microM) had any neuroprotective effects, as determined by counting microtubule-associated protein-2 positive cells and lactate dehydrogenase assay 24 h after the glutamate treatment. Unexpectedly, gamma-vinyl-GABA alone induced a 20% loss of microtubule-associated protein-2-positive cells in a culture that was grown in medium containing 25 mM KCl. The toxic effect of gamma-vinyl-GABA was mimicked by a 24-h treatment with GABA (100 microM) and the GABA(A) receptor agonist, muscimol (10 microM), but not the GABA(B) receptor agonist, baclofen (10 microM). The GABA(A) receptor antagonist, bicuculline (10 microM), protected against gamma-vinyl-GABA and GABA-evoked toxicity. Neither gamma-vinyl-GABA nor GABA was toxic in culture medium containing 15 mM KCl. These data indicate that, under depolarizing conditions, an increased GABA level is toxic for a subpopulation of developing hippocampal neurons in vitro. The effect is GABA(A) receptor-mediated. These data provide a new view for understanding neurodegenerative processes, and raise a question of the safety of therapies aimed at increasing GABA concentration following brain insults, especially in immature brains.     

Endothelin-1 Induced Middle Cerebral Artery Occlusion Model for Ischemic Stroke with Laser Doppler Flowmetry Guidance in Rat

Stroke is the number one cause of disability and third leading cause of death in the world, costing an estimated $70 billion in the United States in 2009^{1, 2}. Several models of cerebral ischemia have been developed to mimic the human condition of stroke. It has been suggested that up to 80% of all strokes result from ischemic damage in the middle cerebral artery (MCA) area³. In the early 1990s, endothelin-1 (ET-1) ⁴ was used to induce ischemia by applying it directly adjacent to the surface of the MCA after craniotomy. Later, this model was modified ⁵ by using a stereotaxic injection of ET-1 adjacent to the MCA to produce focal cerebral ischemia. The main advantages of this model include the ability to perform the procedure quickly, the ability to control artery constriction by altering the dose of ET-1 delivered, no need to manipulate the extracranial vessels supplying blood to the brain as well as gradual reperfusion rates that more closely mimics the reperfusion in humans^5-7. On the other hand, the ET-1 model has disadvantages that include the need for a craniotomy, as well as higher variability in stroke volume⁸. This variability can be reduced with the use of laser Doppler flowmetry (LDF) to verify cerebral ischemia during ET-1 infusion. Factors that affect stroke variability include precision of infusion and the batch of the ET-1 used⁶. Another important consideration is that although reperfusion is a common occurrence in human stroke, the duration of occlusion for ET-1 induced MCAO may not closely mimic that of human stroke where many patients have partial reperfusion over a period of hours to days following occlusion^{9, 10}. This protocol will describe in detail the ET-1 induced MCAO model for ischemic stroke in rats. It will also draw attention to special considerations and potential drawbacks throughout the procedure.     

miR-146aC>G,miR-149T>C基因多态性与缺血性脑卒中易感性的研究

目的:探讨中国汉族人群中miR-146aCG,miR-149TC基因多态性与缺血性脑卒中易感性的关系。方法:利用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)的方法检测196例缺血性脑卒中患者和205例健康对照中miR-146aCG,miR-149TC的基因型,统计学方法比较两组间基因型及等位基因分布差异。结果:miR-146aCG位点各基因型在病例组和对照组分布无明显差异,但等位基因G会增加缺血性脑卒中的患病风险;miR-149TC位点各基因型在病例组和对照组分布无明显差异。在分层分析中,miR-146aCG会增加女性和非高血压患者缺血性脑卒中的患病风险,miR-149TC会增加非高血压患者缺血性脑卒中的患病风险。结论:miR-146aG等位基因,miR-149C等位基因与汉族人群缺血性脑卒中易感性有一定的相关性。     

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As such, primary or ''neuronal-like'' cell culture systems are commonly utilized. While these systems are relatively easy to work with, and are useful model systems in which various functional outcomes (such as cell death) can be readily quantified, the examined outcomes and pathways in cultured immature neurons (such as excitotoxicity-mediated cell death pathways) are not necessarily the same as those observed in mature brain, or in intact tissue. Therefore, there is the need to develop models in which cellular mechanisms in mature neural tissue can be examined. We have developed an in vitro technique that can be used to investigate a variety of molecular pathways in intact nervous tissue. The technique described herein utilizes rat cortical tissue, but this technique can be adapted to use tissue from a variety of species (such as mouse, rabbit, guinea pig, and chicken) or brain regions (for example, hippocampus, striatum, etc.). Additionally, a variety of stimulations/treatments can be used (for example, excitotoxic, administration of inhibitors, etc.). In conclusion, the brain slice model described herein can be used to examine a variety of molecular mechanisms involved in excitotoxicity-mediated brain injury.