缺血后处理对脑缺血再灌注损伤大鼠的脑保护作用及其最佳时间窗的探讨

目的探讨缺血后处理(IP)对大鼠局灶性脑缺血再灌注(I/R)神经保护作用的最佳时间窗。方法 80只雄性SD大鼠,随机分为5组(假手术组、对照组、IP 15s组、IP 30s组和IP 1min组)。假手术组和对照组行单纯I/R;IP 15s组、IP 30s组和IP 1min组,反复3次缺血再灌注。除假手术组外的大鼠均采用线栓法闭塞大鼠大脑中动脉(MACO)建立脑缺血SD大鼠模型。所有大鼠行神经功能障碍评分(NDS),并应用组织原位标记凋亡细胞检测、免疫组织化学等技术观察IP后海马CA1区细胞凋亡及肿瘤坏死因子(TNF-α)表达的变化。结果再灌注24 h后,IP各组NDS明显低于对照组(P<0.05),其中IP 15s组、IP 30s组NDS低于IP 1min组(P<0.05)。对照组海马CA1区TNF-α、凋亡细胞表达量明显增加,IP 15s组、IP 30s组海马CA1区TNF-α、凋亡细胞的表达量较IP 1min组明显下降(P<0.05)。结论 IP可改善局灶性脑缺血大鼠的神经功能、减少海马CA1区炎性因子TNF-α及细胞凋亡的表达。大鼠局灶性脑缺血再灌注损伤保护作用的最佳时间窗为15s、30s。     

缺血后处理通过水通道蛋白-4对大鼠缺血再灌注损伤的脑保护作用及其机制

目的研究缺血后处理(IP)对大鼠脑缺血再灌注损伤的保护作用,探讨各组大鼠水通道蛋白-4(AQP4)的表达。方法实验分组:48只雄性SD大鼠,随机分为3组(n=16)。假手术组;对照组:行单纯缺血再灌注;缺血后处理组:IP组。采用线栓法阻断大脑中动脉制备大鼠局灶性脑缺血再灌注模型。大鼠脑缺血再灌注后24 h进行神经行为学评分和脑梗死体积测定,干湿重法测定脑水含量。并行免疫组织化学方法检测海马CA_1区细胞凋亡及AQP4表达的变化并行统计学分析。结果与对照组比较,IP组神经行为学评分明显降低,脑梗死体积、脑组织中的水分含量明显减少(P 0. 05)。再灌注24 h后,对照组海马CA_1区AQP4、凋亡细胞24 h表达量明显增加,IP组与对照组之间比较有差异(P 0. 05)。结论 IP组脑神经行为学评分、脑含水量、脑梗死体积均明显降低,提示缺血后处理可通过抑制AQP4的表达减轻缺血再灌注损伤后的脑水肿,起到脑保护作用。     

氯喹对大鼠全脑缺血/再灌注后学习能力的影响

目的观察氯喹对大鼠全脑缺血/再灌注后的学习能力的影响。方法采用Pulsinelli-Brierley 4动脉阻断方法制作大鼠全脑缺血/再灌注损伤模型,使用HE染色方法观察各组大鼠海马区的损伤情况,用Y型电迷宫检测各组大鼠的学习记忆能力。结果氯喹处理组大鼠海马区损伤较缺血损伤组大鼠减轻,氯喹处理组大鼠学习记忆能力强于缺血损伤组大鼠,但仍比假手术组大鼠差（P〈0.05）。结论氯喹可以通过减轻大鼠全脑缺血后海马损伤减轻学习记忆能力的损伤。     

缺血后处理对大鼠脑缺血/再灌注后海马CA_1区神经元凋亡及β淀粉样蛋白1-40表达的影响

目的探讨缺血后处理(ischemic postconditioning,IP)对脑缺血/再灌注(ischemia/reperfusion,I/R)后大鼠海马CA1区神经元凋亡及β淀粉样蛋白1-40(β-Amyloid Prote in 1-40,Aβ1-40)表达的影响。方法40只雄性SD大鼠随机分为假手术(SH)组、I/R组、IP组。用线栓法建立大鼠大脑中动脉缺血模型,脑缺血60m in后进行不同时间点的缺血后处理,恢复再灌注24h后行神经行为学评分(NDS),检测神经元凋亡及Aβ1-40的表达。结果与I/R组比较,IP组显著改善NDS(P<0.01),显著减少海马CA1区神经元凋亡(P<0.01)及Aβ1-40表达水平(P<0.01)。Aβ1-40的表达与细胞凋亡呈正相关(r=0.845,P<0.01)。结论缺血后处理可通过抗细胞凋亡机制减轻脑缺血/再灌注损伤。缺血/再灌注后Aβ1-40表达上调,缺血后处理可减少缺血/再灌注后Aβ1-40表达。Aβ1-40可能参与缺血后处理抗细胞凋亡的脑保护机制。     

用Morris全自动水迷宫评价Sprage Dawley鼠全脑反复缺血后学习记忆功能研究

目的　评价大鼠脑缺血后的学习、记忆功能及其与海马组织学变化的关系。方法　用Morris全自动新式水迷宫试验方法对反复脑缺血再灌注大鼠进行学习获得试验、记忆保持试验 ,光镜观察海马组织学变化 ,并计算海马神经元密度。结果　与对照组比较 ,反复脑缺血大鼠学习记忆成绩显著下降 ,潜伏期显著延长 ,游水迷宫形呈周边型 ;缺血后海马CA1、CA4 和PM区神经元大量丧失。结论　大鼠反复脑缺血出现严重的学习、记忆障碍。认知功能改变与海马神经元缺血性损害有关。用Morris全自动水迷宫评价缺血所致学习、记忆障碍简便、准确、真实。     

盐酸多奈哌齐对血管性痴呆小鼠学习和记忆能力的影响

目的观察盐酸多奈哌齐对脑缺血-再灌注后血管性痴呆小鼠不同时间点学习、记忆能力和海马CA1区病理变化的影响。方法雄性昆明小鼠250只,采用双侧颈总动脉反复缺血-再灌注的方法制备血管性痴呆(VD)模型,随机分为假手术组、模型组和多奈哌齐治疗组。应用Morris水迷宫实验、跳台实验进行行为学测试,HE染色观察海马病理表现及盐酸多奈哌齐对其的影响。结果术后4周时,模型组小鼠的学习、记忆成绩均明显劣于假手术组小鼠(P<0.05),病理改变较假手术组严重,这一变化持续至术后8周仍未恢复。盐酸多奈哌齐治疗组在术后4周和8周时,其学习、记忆能力和海马CA1区病理表现较模型组均有明显改善(P<0.05)。结论脑缺血-再灌注可导致小鼠海马CA1区神经元持续进行性损害,伴学习、记忆能力障碍;盐酸多奈哌齐对脑缺血-再灌注诱发的VD小鼠有一定治疗作用。     

缺血后处理对大鼠脑缺血再灌注后紧密连接的保护作用及ZO-1蛋白表达的影响

目的观察缺血后处理对脑缺血再灌注后紧密连接的保护作用及相关蛋白ZO-1表达的影响。方法 45只Wistar雄性大鼠随机分为假手术(Sham)组、缺血再灌注(I/R)组、缺血后处理(IP)组。采用线栓法建立大鼠大脑中动脉缺血模型,脑缺血2 h后,I/R组予再灌注,IP组给予缺血后处理之后予再灌注。于脑缺血再灌注后24 h行TTC染色观察脑梗死体积,应用电镜观察紧密连接蛋白结构改变,Western blot观察ZO-1蛋白表达的变化。结果 IP组脑梗死体积明显小于I/R组,与Sham组相比,I/R组血脑屏障紧密连接开放,ZO-1蛋白表达明显减少;与I/R组比较,IP组紧密连接开放程度减轻及ZO-1表达增加。结论缺血后处理减小脑梗死体积;缺血后处理能够减轻紧密连接破坏,其保护机制可能与ZO-1蛋白表达增加有关。     

丁香酚吸嗅对MCAO模型大鼠脑源性神经营养因子的影响

目的研究丁香酚吸嗅对MCAO模型SD大鼠认知和记忆能力的行为学的影响,评价其对脑缺血后再灌注损伤的干预作用及其可能的作用机制。方法将80只SD雄性大鼠,随机分为正常组、模型组、丁香酚组和假手术组,每组20只。采用大脑中动脉内线栓阻断法(MCAO)制造大鼠局灶性脑缺血再灌注模型,缺血2 h后再灌注24 h。给予相应处理3 w后,大鼠行神经行为学评分后处死,取大脑行2,3,5-氯化三苯基四氮唑(TTC)染色,计算脑梗死容积百分比;Morris水迷宫实验检测学习记忆能力;并利用免疫组织化学染色法观察脑源性神经营养因子(BDNF)在海马CA3区的表达。结果丁香酚吸嗅组干预3 w后与模型组比较神经功能评分差异有显著性(P<0.01);TTC染色梗死面积明显减少(P<0.01),Morris水迷宫实验差异有显著性(P<0.05);海马CA3区BDNF的表达显著性增多。结论丁香酚吸嗅对MACO模型大鼠的损伤有明显的保护作用,其机制可能是提高脑内BDNF含量,调节脑区功能,从而达到对脑缺血再灌注损伤的防治作用。     

亚硒酸钠对脑缺血再灌注损伤大鼠HIF-1α表达的影响

目的 研究亚硒酸钠对大鼠脑缺血再灌注损伤后海马神经细胞凋亡的保护作用及其对低氧诱导因子-1α(HIF-1α)表达的影响.方法 48只SD大鼠随机分为假手术组、缺血再灌注组(模型组)及亚硒酸钠治疗组,每组16只,采用线栓法建立脑缺血再灌注模型,治疗组于再灌注后给予亚硒酸钠0.625 mg/(kg·d)腹腔注射7 d.各组大鼠经组织处理后用亚甲兰尼氏体染色及TUNEL染色,分别观察大鼠海马CA1区神经元存活和凋亡情况,Western Blot实验测定缺血组织HIF-1α水平的表达.结果 脑缺血再灌注损伤大鼠海马神经元数目明显减少,凋亡细胞明显增加(P<0.001),亚硒酸钠治疗后海马神经细胞存活数目明显增多,凋亡细胞明显减少(P<0.01);与假手术组比较,模型组大鼠海马HIF-1α水平表达明显增加(P<0.01),而经亚硒酸钠治疗后大鼠海马HIF-1α水平表达较模型组明显降低(P＜0.05).结论 亚硒酸钠可减轻脑缺血再灌注损伤大鼠神经元凋亡,同时能抑制组织HIF-1α的过度表达.     

缺血后处理通过NMDA受体对全脑缺血大鼠的神经保护作用

目的观察缺血后处理对大鼠全脑缺血再灌注损伤的神经保护作用,并探讨NMDA受体在该过程中的作用。方法采用4-VO法制备全脑缺血模型,将30只SD大鼠完全随机分为假手术组(S组)、全脑缺血(15 min)再灌注组(I/R组)、缺血后处理组(15 s/15 s,3cycle)(IP组)、NMDA受体阻滞剂MK-801预处理组(IP+MK-801组)、NR2B选择性受体阻滞剂ifenprodil预处理组(IP+ifenprodil组),以水迷宫、旷场实验及神经功能缺损评分评价其对行为学的影响,以尼氏染色法观察大鼠海马CA1区存活细胞的变化。结果与全脑缺血组大鼠相比,缺血后处理组大鼠逃避潜伏期缩短,穿越平台增加,旷场试验评分及神经功能缺陷评分更低,病理形态学改变减轻,每250μm存活神经元数增多,差异均有统计学意义(P<0.05);上述改变均被MK-801阻断,与缺血后处理组有统计学差异(P<0.05),IP+ifenprodil组的表现与缺血后处理组未见差异。结论 NMDA受体可能参与缺血后处理对全脑缺血大鼠的神经保护作用。     

Remifentanil postconditioning improves global cerebral ischemia-induced spatial learning and memory deficit in rats via inhibition of neuronal apoptosis through the PI3K signaling pathway

Global cerebral ischemia followed by reperfusion, which leads to extensive neuronal damage, particularly the neurons in the hippocampal CA1 region. Apoptosis is one of the major mechanisms that lead to neuronal death after cerebral ischemia and reperfusion. The neuroprotective effects of remifentanil preconditioning against cerebral ischemia/reperfusion injury have been recently reported. Here we investigated whether remifentanil postconditioning exerts neuroprotective effects against global cerebral ischemia/reperfusion injury in rats and its potential mechanisms. Global cerebral ischemia was performed via 10 min of four-vessel occlusion. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positive cells and expression of Bcl-2 and Bax in the hippocampal CA1 region were assessed after reperfusion. Morris water maze task was used to quantify spatial learning and memory deficits after reperfusion. We found remifentanil postconditioning markedly improved the spatial learning and memory as well as attenuated neuronal apoptosis in hippocampus caused by cerebral ischemia/reperfusion injury. In addition, remifentanil postconditioning enhanced the expression of anti-apoptotic gene Bcl-2 while suppressed the expression of pro-apoptotic gene Bax in hippocampal CA1 region. However, the neuroprotective effects of remifentanil postconditioning were abolished by pretreatment of the PI3K inhibitor LY294002. The results suggest that remifentanil postconditioning exhibits neuroprotective effects against global cerebral ischemia/reperfusion injury in rats, and its mechanisms might involve inhibition of neuronal apoptosis through the PI3K pathway.     

盐酸法舒地尔对慢性脑低灌注损伤大鼠海马细胞的保护作用

目的 观察Rho激酶抑制剂盐酸法舒地尔(hydroxy fasudil, HF)对慢性低灌注脑缺血所致大鼠海马神经细胞损伤的保护作用。方法 采用永久性结扎大鼠双侧颈总动脉(permanent occlusion of the bilateral CCA, 2VO)制备大鼠慢性不完全性全脑缺血模型,将SD大鼠随机分为假手术组、脑缺血模型组和HF治疗组,运用Morris 水迷宫行为学方法检测大鼠空间学习记忆能力; 用HE染色观察海马组织形态学改变。结果 Morris 水迷宫检测发现模型组大鼠学习记忆能力受损,与假手术组比较逃避潜伏期延长、空间辨别能力下降; 组织学观察模型组大鼠海马CA1细胞发生丢失,组织结构异常。连续给予盐酸法舒地尔30 d能改善大鼠学习记忆功能,减少脑缺血所致的大鼠海马神经细胞丢失。结论 盐酸法舒地尔可减少慢性脑缺血所致的大鼠海马神经元的丢失,改善学习记忆功能。     

γ-氨基丁酸对慢性脑缺血致血管性痴呆大鼠学习记忆能力的影响

目的观察γ-氨基丁酸（GABA）对慢性脑缺血致血管性痴呆（VD）大鼠学习记忆能力及海马CA1区神经元形态学的影响。方法将SD大鼠随机分为假手术组、模型组、GABA组,采用双侧颈总动脉永久性结扎法建立VD模型。GABA组术后腹腔注射GABA0.5g.kg-1.d-1,连续注射60d;用Morris水迷宫实验检测大鼠空间学习记忆能力;Nissl染色观察大鼠海马CA1区神经元形态学变化。结果 GABA能明显改善VD大鼠学习记忆能力,也能减轻海马CA1区神经元损伤。结论 GABA能改善慢性脑缺血致VD大鼠的学习记忆能力,减轻海马神经元损伤可能是其机制之一。     

Preconditioning with sevoflurane ameliorates spatial learning and memory deficit after focal cerebral ischemia–reperfusion in rats

Previous studies have demonstrated that sevoflurane could attenuate cerebral neuron necrosis and apoptosis in ischemia–reperfusion models in rats. The aim of our study was to investigate the effect of preconditioning with sevoflurane on spatial learning and memory ability after focal cerebral ischemia–reperfusion injury in rats and its potential mechanisms. Focal cerebral ischemia was performed via 1 h of middle cerebral artery occlusion (MCAO) followed by reperfusion. Before ischemia, rats were subjected to preconditioning with inhalation of 2.4% sevoflurane for 1 h. The spatial learning and memory ability of rats was measured by the Morris water maze. The activity of choline acetyltransferase (ChAT) in hippocampus CA1 region was observed by immunohistochemistry method. We found MCAO elicited a significant decrease of the ability of spatial learning and memory in contrast to the sham surgery controls. However, preconditioning with sevoflurane resulted in significantly ameliorates spatial learning and memory deficit induced by MCAO. Furthermore, the number of ChAT positive cells in hippocampus CA1 region in sevoflurane preconditioning group was striking more than that of ischemia–reperfusion group. All results suggested that preconditioning with 2.4% sevoflurane could ameliorate the ability of spatial learning and memory after focal cerebral ischemia–reperfusion in rats via protecting the cholinergic neurons in hippocampal CA1 region.     

Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia

Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral ischemic injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule(5 days per week for 4 weeks). Then rats underwent cerebral ischemia induction th rough occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-ischemic exercise significantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-ischemic exercise significantly prevented ischemia-induced memory dysfunction. Pre-ischemic exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration.     

慢性脑缺血海马CA1区HCN1蛋白表达下调与学习记忆损伤研究

目的 探讨慢性脑缺血导致大鼠认知功能障碍与HCN1通道亚型蛋白表达变化的内在关系。方法 健康成年雄性SD大鼠20只,随机分为假手术组、缺血组,每组各10只。各组缺血4周后采用Morris水迷宫检测大鼠学习记忆功能,免疫组化检测HCN1表达水平,进一步用蛋白印迹检测HCN1蛋白表达水平。结果 与假手术组相比,缺血组大鼠逃避潜伏期明显延长(P<0.05); 缺血组大鼠海马CA1区HCN1蛋白表达水平明显降低,与模型组比较有明显差异(P<0.05)。结论 慢性脑缺血海马CA1区存在HCN1通道亚型表达下调且参与大鼠认知功能损伤,可能为治疗慢性脑缺血所致认知功能障碍的新靶点。     

全脑缺血-再灌注对海马CA1区GAD65表达的影响及意义

目的探讨全脑缺血-再灌注对成年大鼠海马CA1区GAD65表达的影响及意义。方法成年雄性SD大鼠24只,随机分为3组:假手术组(SH)、缺血-再灌注3d组(IR-3)及缺血-再灌注7d组(IR-7),每组8只。采用四动脉阻断法制作全脑缺血-再灌注模型,应用免疫组织化学方法检测海马CA1区谷氨酸脱羧酶(glutamic acid decarboxylase,GAD)同工酶GAD65的表达变化。结果与假手术组相比,IR-3组GAD65的表达明显增多,IR-7组恢复正常。结论GABA能中间神经元对缺血相对耐受;全脑缺血-再灌注3dGAD65的表达增多可能是一种代偿性的机制,以减轻脑缺血后的高兴奋性。