尼古丁对大鼠局灶性脑缺血再灌注损伤的神经保护作用

目的:研究尼古丁对大鼠局灶性脑缺血再灌注损伤是否具有神经保护作用。方法:在大鼠大脑中动脉堵塞(MCAO)前30min给予腹腔注射尼古丁酒石酸盐溶液,观察局灶性脑缺血2h再灌注24h后,大鼠神经行为学评分及脑梗死容积的变化。结果:再灌注24h后,与单纯缺血再灌注组相比,给予尼古丁酒石酸盐溶液注射可以改善动物的神经行为学评分、减少脑梗死容积百分比(P0.05)。结论:尼古丁对大鼠局灶性脑缺血再灌注损伤具有神经保护作用。     

人参皂甙Rd在脑缺血亚急性期的脑保护效应

目的:探讨人参皂甙Rd(Ginsenoside Rd,GSRd)在脑缺血亚急性期的脑保护效应。方法:84只雄性SD大鼠随机分为四组,其中假手术+丙二醇(propylene glycol,PG)组和假手术+GSRd组各18只,脑缺血+PG组和脑缺血+GSRd组各24只。线栓法建立局灶性短暂性大脑中动脉栓塞模型(focal transient middle cerebral ar-tery occlusion,MCAO),栓塞后1 d经腹腔注射GSRd和PG。在用药前、用药后3 d和7 d分别进行神经功能评分(neurological behavior scores,NBS),每次评分后取脑进行2,3,5-氯化三苯基四氮唑(TTC)染色,用ImageJ图像分析软件计算出梗死体积百分比,并且对缺血区或半暗带进行Iba 1染色,观察小胶质细胞的变化情况以确定GSRd对脑缺血后炎性反应的影响作用。结果:脑缺血后1 d开始给予GSRd能改善MCAO模型大鼠的神经功能评分,减少脑梗死体积减弱小胶质细胞的活化,与PG组相比具有统计学差异(P<0.05)。结论:在脑缺血亚急性期给予GSRd能够起到脑保护作用。     

移植BDNF和GDNF基因修饰的hMSCs对大鼠大脑中动脉阻塞的影响

 目的：构建脑源性神经营养因子（BDNF）和胶质细胞源性神经营养因子（GDNF）基因的非病毒表达载体,用脂质体法转染人骨髓间充质干细胞（hMSCs）,观察其对大鼠大脑中动脉阻塞（MCAO）模型的影响,探索移植转基因修饰的hMSCs治疗脑血管疾病的可行性。方法：构建高效非病毒表达载体,用脂质体法转染获得高表达2种神经营养因子的hMSCs。建立大鼠MCAO模型,建模后24 h经股静脉进行转基因hMSCs移植,并以磷酸盐缓冲液(PBS)和hMSCs为对照。用脑梗死体积计算、体重变化、行为学评测等指标对大鼠脑损伤程度进行评估,通过大鼠脑组织观察和病理切片对脑组织损伤以及细胞的迁移分化情况进行分析。结果：经股静脉转基因hMSCs移植能够提高大鼠MCAO后的感觉运动功能,减小脑梗死体积,与PBS对照组相比有显著差异;与hMSCs治疗组相比,治疗效果较好且稳定。移植的细胞在脑损伤区域有少数存活但未见分化现象。结论：经静脉移植脂质体介导、GDNF和BDNF基因修饰的hMSCs,可促进缺血脑组织的损伤修复,效果较好,为非病毒载体在干细胞相关转基因治疗的应用提供了理论依据。本研究表明,MSCs的作用不依赖干细胞的分化和神经元的替换,而可能与其分泌细胞因子对抗脑损伤并促进神经修复有关,在MSCs中转入特定的外源性神经营养因子可加强这一作用。     

Ghrelin对脑缺血再灌注大鼠脑水肿和水通道蛋白4表达的影响

 目的： 探讨ghrelin对脑缺血再灌注大鼠脑水肿、血脑屏障通透性及水通道蛋白4（AQP4）表达的影响。方法： 成年SD雄性大鼠随机分为3组:sham组、大脑中动脉阻塞（MCAO）组和ghrelin处理组。采用线栓法复制MCAO模型（缺血2 h,再灌注22 h）。Ghrelin组大鼠于再灌开始时经股静脉注射ghrelin 10 nmol/kg。TTC染色观察脑梗死体积,神经功能评分判断脑功能障碍程度,分别以体积计算和干湿重法检测脑肿胀程度和脑含水量的变化,收集脑血管外伊文思蓝(EB)来评估血脑屏障的破坏程度,免疫组化和Western blotting检测AQP4的表达变化。结果： 与MCAO组比较,ghrelin处理组的脑梗死体积较小（P<0.01）,神经功能评分较低（P<0.01）,脑组织中的EB渗出量较少（P<0.01）。Ghrelin处理组大鼠的脑肿胀体积、脑含水量和AQP4表达明显低于MCAO组（P<0.05）。结论： Ghrelin减轻大鼠脑缺血/再灌注损伤,减轻脑水肿和血脑屏障的破坏,抑制脑组织中AQP4的表达。AQP4在ghrelin的脑保护机制中可能发挥重要作用。     

Rapid tolerance to focal cerebral ischemia in rats is induced by preconditioning with electroacupuncture: window of protection and the role of adenosine

The aim of the present study was to investigate the first protective window of preconditioning with electroacupuncture (EA) against focal cerebral ischemia, and to explore whether adenosine is involved in the rapid tolerance phenomenon. Sixty-four male Sprague-Dawley rats were randomly assigned to eight groups (n=8 in each). Animals in the control group received no treatment, and animals in EA1-EA4 groups received EA at 0.5, 1, 2 and 3 h before induction of focal cerebral ischemia, respectively. Rats in DPCPX group were intraperitoneally injected with 1 mg kg-1 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), 3 h before induction of focal cerebral ischemia. Animals in vehicle group and EA+DPCPX group were pretreated with 1 ml kg-1 dimethyl sulfoxide (DMSO, the solvent of DPCPX) and 1 mg kg-1 DPCPX 30 min before preconditioning with EA, respectively. All rats were anesthetized with 40 mg kg-1 pentobarbital sodium intraperitoneally. Animals that required EA preconditioning, received EA with intensity of 1 mA and frequency of 15 Hz at the Baihui acupoint (GV 20) for 30 min. The focal cerebral ischemia was produced by the right middle cerebral artery occlusion (MCAO) for 120 min. The neurologic deficit scores (NDS) and brain infarct volumes were evaluated at 24 h after reperfusion. All rats survived until 24 h after reperfusion. Preconditioning with EA at 2 h before induction of focal cerebral ischemia improved neurologic outcome (P<0.05 versus control) and reduced the infarct volume (P<0.01 versus control) at 24 h after reperfusion. These beneficial effects were reversed by pretreatment with 1 mg kg-1 DPCPX, whereas this agent itself did not affect the NDS and volume in drug-ischemic controls after ischemia. The results show that preconditioning with single EA session induces rapid tolerance to focal cerebral ischemia. The rapid ischemic tolerance appears at 2 h (but not at 0.5, 1, or 3 h) after preconditioning, and is possibly mediated through an adenosine A1 receptor-related mechanism.     

小鼠脑缺血时自噬相关基因5的抗损伤作用

 目的: 观察自噬相关基因5(Atg5)在小鼠脑缺血再灌注损伤中的抗损伤作用。方法: 将雄性BALB/c小鼠随机分为假手术(sham)组、缺血再灌注(I/R)组、Atg5 siRNA组和control siRNA组。I/R组采用大脑中动脉阻塞(MCAO)60 min后再灌注24 h。Atg5 siRNA组和control siRNA组将5 μL Atg5 siRNA或scrambled siRNA在MCAO前24 h侧脑室注射。实时荧光定量PCR和Western blot检测Atg5的表达;2,3,5-氯化三苯基四氮唑(TTC)染色法检测抑制Atg5对缺血再灌注损伤后脑梗死面积和水肿率的影响;神经行为学评分法检测抑制Atg5对缺血再灌注损伤后神经症状的影响。结果: MCAO后再灌24 h,缺血半影区Atg5 mRNA和蛋白水平显著增高(P<0.05);Atg5 siRNA明显降低缺血再灌后Atg5 mRNA和蛋白的表达(P<0.05);侧脑室给予Atg5 siRNA能显著增加脑梗死面积和水肿率,并加重神经行为学损伤(P<0.05)。结论: 沉默Atg5加重小鼠脑缺血再灌损伤,提示MCAO后诱导的 Atg5 可减轻小鼠局灶性脑缺血再灌注损伤。     

他米巴罗汀减轻大鼠脑缺血再灌注损伤

目的探讨他米巴罗汀(Am80)对大鼠脑缺血再灌注损伤(CIR)的作用。方法将大鼠随机分为:假手术组(sham)、模型组(I/R)和他米巴罗汀干预组(Am80,灌胃给予Am80 6 mg/kg)。采用线栓法建立大脑中动脉栓塞(MCAO)模型。术后24 h断头取脑,在处死前采用双盲法进行神经行为学评分;TTC染色测定脑梗死体积;Western blot和RT-q PCR法分别检测RARα、Bcl-2和Bax蛋白及mRNA的表达。结果 Am80可显著改善MCAO大鼠神经功能缺损,有效地降低脑梗死体积(P0.01),上调RARα和Bcl-2表达(P0.01),降低Bax的表达(P0.01)。结论他米巴罗汀对脑缺血再灌注损伤大鼠有保护作用,其作用可能与抗凋亡有关。     

P-糖蛋白在永久性脑缺血大鼠脑内的表达

目的:研究脑缺血后多药耐药蛋白(P-glycoprotein,P-gp)在脑内血管及细胞中的表达变化,探讨P-gp与脑缺血的关系。方法:应用微创开颅法建立大鼠大脑中动脉闭塞(MCAO)模型,30只大鼠随机分为缺血后1、2、3 d共3个缺血组,以及正常对照组和假手术组(n=6)。用抗P-gp抗体进行免疫组化染色观测血管壁及脑内细胞是否表达P-gp以及缺血后不同时间点的表达变化。结果:缺血后1、2、3 d组中,在缺血坏死区可见大量表达P-gp的阳性细胞,3 d时达高峰;缺血区仅有少量血管表达P-gp,在缺血区周围皮质及纹状体中血管壁上大量表达P-gp,并随缺血时间的延长而显著增多,在3 d组达高峰。结论:脑缺血后大鼠脑内血管壁及细胞中大量表达P-gp,提示脑内受损后多药耐药蛋白合成增加,在自我保护的同时也影响了临床药物的进入。     

尾静脉注射骨髓基质细胞和腹腔注射粒细胞集落刺激因子治疗大鼠脑梗死

背景：骨髓间充质干细胞具有成神经分化特性,有很多试验也证实粒细胞集落刺激因子可以用于改善脑梗死后的神经功能。 目的：比较静脉移植骨髓间充质干细胞和腹腔注射粒细胞集落刺激因子动员干细胞来治疗大脑中动脉闭塞模型大鼠疗效。 方法：实验以改良的Zea-longa线栓法阻断大脑中动脉建立SD大鼠脑梗死模型,造模24 h后分别通过尾静脉注射骨髓间充质干细胞或腹腔注射粒细胞集落刺激因子。 结果与结论：两种治疗方法均可改善脑梗死模型大鼠的运动和认知功能,且粒细胞集落刺激因子对脑梗死模型大鼠的运动和认知功能的改善比尾静脉注射骨髓间充质干细胞明显,移植后第7,14天,粒细胞集落刺激因子组梗死面积小于骨髓间充质干细胞组(P < 0.05),粒细胞集落刺激因子组BrdU阳性细胞数多于骨髓间充质干细胞组(P < 0.05)。提示粒细胞集落刺激因子动员骨髓干细胞治疗脑梗死的疗效可能优于骨髓间充质干细胞静脉注射的移植方法。     

川芎嗪联合骨髓间充质干细胞移植抑制脑缺血大鼠神经细胞凋亡

目的:研究川芎嗪(tetramethylpyrazine,TMP)联合骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)对脑缺血大鼠神经细胞凋亡及Bcl-2、Bax表达的影响。方法:采用全骨髓贴壁法体外培养BMSCs,传代至第3代用于尾静脉移植。采用线栓法诱导大鼠右侧大脑中动脉阻塞模型,除假手术组外,大鼠随机分为模型组、BMSCs(1×10~9/L)组、川芎嗪(40 mg/kg)组和联合(川芎嗪+BMSCs)组,每组12只。缺血后第1、7和14天采用改良的神经损伤严重程度评分(modified neurological severity scoring,m NSS)进行神经功能评价。缺血后第14天,甲苯胺蓝染色检测脑梗死体积,HE染色观察脑组织病理学变化,采用原位末端标记(TUNEL)法观察神经细胞凋亡数,采用实时荧光定量PCR法和Western blot法检测Bax和Bcl-2的mRNA及蛋白表达。结果:与BMSCs组和川芎嗪组比较,联合组m NSS评分显著减少(P0.01),梗死体积显著减少(P0.01),缺血引起的脑缺血周边区病理性损伤明显减轻,TUNEL阳性细胞数显著减少(P0.01),Bcl-2的mRNA及蛋白表达显著增加,Bax的mRNA及蛋白表达显著降低(P0.01)。结论:川芎嗪联合BMSCs移植能显著促进脑缺血后大鼠的功能恢复,减少梗死体积,减轻脑组织缺血性损伤,抑制神经细胞凋亡,机制可能与调控Bcl-2和Bax的表达有关。     

The role of tumor necrosis factor-alpha in stress-induced worsening of cerebral ischemia in rats

Whereas stress is known to be one of the risk factors of stroke, few experimental studies have examined the possible mechanisms by which stress may affect stroke outcome. Most of the knowledge on the effects of stress on cerebrovascular disease in humans is restricted to catecholamines and glucocorticoids effects on blood pressure and/or development of atherosclerosis. By using an experimental paradigm consisting of the exposure of Fischer rats to repeated immobilization sessions (1 h daily during seven consecutive days) prior to permanent middle cerebral artery occlusion (MCAO), we have found that stress worsens behavioral outcome and increases infarct size after MCAO. These changes occur concomitantly to an increase in inducible nitric oxide synthase (iNOS) expression and to the accumulation of lipid peroxidation markers in brain tissue. The possible regulatory role of TNFalpha was studied by looking at the mechanisms of release of this cytokine as well as to the expression of its receptors (TNFR1 and 2). The results of the present study suggest an increase in TNFalpha expression and release after stress, as well as an increase in the expression of TNFR1. Pharmacological blockade of TNFalpha with anti-TNFalpha led to a decrease in the infarct size as well as in the oxidative/nitrosative biochemical parameters seen after ischemia. In summary, our results indicate that TNFalpha accounts, at least partly, for the worsening of MCAO consequences in brain of rats exposed to stress. Furthermore, the data presented here provide evidence that stress can increase brain ischemic damage and support a possible protective effect of treatment of stressful situations before and during the development of the brain ischemia.     

Hyperbaric oxygen treatment attenuated the decrease in regional glucose metabolism of rats subjected to focal cerebral ischemia: a high resolution positron emission tomography study

Cerebral hypoxia may be the main component of cell damage caused by ischemia. Previous studies demonstrated a neuroprotective effect of early hyperbaric oxygen (HBO) treatment in various animal models of focal cerebral ischemia. Neuropathologic study showed that exposure of HBO may prevent cell death in ischemic cortex. In the present study, we aimed to assess cellular function of ischemic rat brain after HBO treatment by means of a high-resolution positron emission tomography scanner (microPET) used specifically for small animal imaging. The male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO), with the regional cerebral blood flow monitored in vivo by laser Doppler flowmetry. One hour after ischemia, HBO therapy (3 atm absolute, 1 h) was initiated. Local cerebral glucose utilization in the ischemic area was measured before, 1 h and 3 h after ischemia, with 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) as a tracer. Neurological deficits and infarct volumes were assessed at 24 h after ischemia. Our study showed that early HBO therapy significantly reduced infarct volume of brain 24 h after ischemia. Moreover, glucose utilization in the ischemic area underwent a severe decrease during 1-3 h after MCAO, while the early HBO treatment significantly attenuated the decrease in cerebral metabolic rate of glucose in the ischemic core of the cortex compared with controls. We report for the first time the application of microPET to quantify the rates of glucose metabolism in the ischemic core of rats exposed to HBO. Our results suggest that the early exposure of HBO can partially reverse the downward trend for glucose utilization in the ischemic core, which might contribute to the reported beneficial effects of early HBO therapy on permanent cerebral ischemia.     

Ferulic acid prevents the cerebral ischemic injury-induced decrease of Akt and Bad phosphorylation

Ferulic acid protects neuronal cells from glutamate-induced excitotoxicity and focal cerebral ischemia. This study investigated whether ferulic acid exerts a neuroprotective effect through the activation of Akt and its downstream targets, Bad and 14-3-3. Adult male rats were immediately treated with ferulic acid (100 mg/kg, i.v.) after middle cerebral artery occlusion (MCAO). Brains were collected 24 h after MCAO and infarct volumes were analyzed using triphenyltetrazolium chloride staining. It was found that ferulic acid treatment significantly reduced infarct volume during MCAO. Ferulic acid attenuated the MCAO injury-induced decrease of phospho-PDK1, phospho-Akt and phospho-Bad levels. However, ferulic acid did not affect the expression of 14-3-3 and Bcl-xL, which exerts an anti-apoptotic effect through interaction with phospho-Bad. Immunoprecipitation analysis demonstrated that the interaction between phospho-Bad and 14-3-3 decreased during MCAO, whereas ferulic acid prevented the injury-induced decrease in these interaction levels. Moreover, ferulic acid prevented the injury-induced increase in cleaved caspase-3 levels. These findings suggest that ferulic acid attenuates cell death during MCAO and that these protective effects are due to inhibition of Akt signaling pathway inactivation and maintenance of the interaction between phospho-Bad and 14-3-3.     

UCF-101对大鼠脑缺血再灌注后凋亡抑制蛋白XIAP表达的影响

目的观察UCF-101对大鼠脑缺血再灌注损伤后神经元凋亡及凋亡抑制蛋白XIAP表达的影响,探讨UCF-101对缺血性脑损伤的神经保护作用。方法采用线栓法建立Wistar大鼠大脑中动脉闭塞(MCAO)2h再灌注模型,随机将大鼠分为假手术组、缺血再灌注组及UCF-101处理组,于再灌注后24h取脑,采用TTC法测梗死体积,TUNEL法检测神经元凋亡,免疫组化法观察脑组织神经元XIAP蛋白的表达。结果假手术组未见梗死现象,偶见凋亡神经细胞,神经元中可见棕黄色XIAP颗粒散在分布于核膜周围胞浆中。与假手术组比较,缺血再灌注组可见梗死灶,脑组织凋亡细胞数明显增加,XIAP的表达明显降低(P<0.05);与缺血再灌注组比较,UCF-101处理组梗死体积明显缩小(P<0.05),脑组织凋亡细胞数减少,XIAP的表达均明显增加(P<0.05)。结论 UCF-101神经保护作用可能与上调脑组织神经元XIAP蛋白的表达和抑制神经元的凋亡有关。     

Baicalin Inhibits TLR2/4 Signaling Pathway in Rat Brain Following Permanent Cerebral Ischemia

Recent work from our laboratory demonstrated that baicalin attenuates inflammatory reaction and cerebral ischemia injury in rats. Toll-like receptor 2 and 4 (TLR2/4) and the downstream nuclear factor-kappa B (NF-κB) signaling pathway, which mediate the inflammatory reaction, are involved in the pathophysiological processes of cerebral ischemia. In this study, we investigated whether baicalin inhibits TLR2/4 signaling pathway in a rat model of permanent focal cerebral ischemia. Adult Sprague–Dawley rats underwent permanent middle cerebral artery occlusion (MCAO). Baicalin was administered by intraperitoneally injected twice at 2 and 12 h after the onset of ischemia. Cerebral infarct area and infarct volume were measured 24 h after MCAO. Expression of TLR2/4, NF-κB, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were determined by RT-PCR or western blot. NO and PGE2 production in rat brain were measured 24 h after MCAO. Serum content of tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) were detected by ELISA. Baicalin reduced cerebral infarct area and infarct volume. Baicalin reduced the expression of TLR2/4 and NF-κB, decreased the expression and activity of iNOS and COX-2 in rat brain. Baicalin also attenuated the serum content of TNF-α and IL-1β. Our results suggest that baicalin inhibits the TLR2/4 signaling pathway in cerebral ischemia, which may be a mechanism underlying the baicalin’s neuroprotection.     

牛磺酸联合安定治疗脑缺血再灌注损伤的实验研究

目的:研究牛磺酸联合安定对实验性脑缺血再灌注损伤大鼠的神经保护作用。方法:SD雄性大鼠随机分为假手术组、脑缺血再灌注损伤组、牛磺酸治疗组(200mg·kg-1)、安定治疗组(10mg·kg-1)、联合治疗组(牛磺酸100mg·kg-1+安定5mg·kg-1),每组12只。采用大脑中动脉栓塞法(MCAO)建立大鼠局灶性脑缺血模型,2h后拔出栓线形成再灌注,再灌注时各组分别给药,脑缺血再灌注损伤组注射等剂量的生理盐水,12h后各组重复注射1次。另分批实验同样5组动物,每组16只,分别于再灌注后10h给药,12h后重复治疗1次。各组中12只动物同先前5组于再灌注后48h观测神经行为学评分、脑梗死体积以及脑含水量测定。每组中余下4只大鼠,2周后行尼氏染色观察脑组织病理学改变。结果:与脑缺血再灌注损伤组相比,缺血后2h、12h联合治疗均能显著降低大鼠神经行为学评分、减少脑含水量、缩小脑梗死体积,同时能明显减轻海马神经元变性坏死(P0.01或P0.05),且其保护作用优于牛磺酸或安定单用组。结论:缺血性脑损害所致急、慢性损伤时牛磺酸联合安定具有明显的神经保护作用。     

脑缺血再灌注损伤模型大鼠参附注射液干预后热休克蛋白70的表达

背景：参附注射液可通过改善微循环,增加组织血氧含量发挥对缺血再灌注损伤的保护作用。 目的：观察参附注射液对大鼠脑缺血再灌注损伤后热休克蛋白70表达的影响。 方法：将SD大鼠随机分为3组：假手术组、大脑中动脉闭塞缺血再灌注损伤模型组、参附注射液组。 结果与结论：应用参附注射液1 d后,改善了缺血再灌注大鼠脑部神经细胞的排列,减轻了胞体肿胀,核固缩等现象,应用3 d后改善更为明显,胞体结构已较清晰,核固缩、溶解程度显著减轻,胞体肿胀现象明显改善。参附注射液组治疗后1,3 d热休克蛋白70表达明显高于假手术组与模型组。提示参附注射液对脑缺血再灌注具有显著的保护作用,其作用可能是通过促进热休克蛋白70的表达来实现的。     

脑的不对称性影响大鼠局灶性脑缺血的结局

为评价左右侧大脑中动脉闭塞(MCAO)对右利大鼠神经行为功能和脑梗死体积的影响,本研究应用四足动物觅食实验筛选右利爪雄性SD大鼠24只,随机分为经左、右侧插线组各12只,8%水合氯醛腹腔注射(300mg/kg)麻醉,线栓法经左、右侧颈外-内动脉插入头端涂有多聚赖氨酸的4-0尼龙线,建立大鼠MCAO缺血2h模型,再灌注72h后评价动物的神经行为功能,测量脑梗死体积。结果表明,所有动物在脑缺血2h神经功能缺损评分最高,再灌注1、24、48和72h经左侧MCAO大鼠显著高于经右侧MCAO大鼠(P<0.05),后者功能明显优于前者,脑梗死体积经左侧插线的大鼠显著大于经右侧插线的大鼠(P<0.05)。研究结果提示,大鼠主侧半球大脑中动脉缺血后,神经功能缺损和脑梗死体积较对侧严重,脑的不对称性影响大鼠局灶性脑缺血的最终结局。     

SIRT1对早期脑缺血大鼠水通道蛋白4表达的影响

目的:检测水通道蛋白4(AQP4)及沉默信息调节因子1(SIRT1)在脑缺血大鼠脑组织中的表达变化,探究SIRT1对AQP4的调节作用,明确二者在脑缺血及脑水肿发生发展中的作用。方法:雄性SD大鼠随机分成假手术组(sham组)和脑缺血模型组(MCAO组),其中MCAO组又分为6 h、12 h、24 h和48 h 4个时点组别。采用线栓法阻塞大脑中动脉建立局灶性脑缺血模型,于相应时点进行神经症状评分,Morris水迷宫检测大鼠学习认知功能,TTC染色观察脑梗死体积,干湿重法检测脑含水量的变化,HE染色观察大脑皮层周围组织神经细胞形态学变化,Western blot检测AQP4、SIRT1和基质金属蛋白酶9(MMP-9)的表达情况。结果:与sham组相比较,随着再灌注时间增加,MCAO组大鼠神经功能评分、脑梗死体积、脑组织通透性和脑组织含水量均持续增加,而大鼠学习认知功能则降低显著,HE染色显示脑缺血大脑皮层周围组织神经元细胞形态不规则,数目减少;Western blot实验结果显示AQP4表达水平呈增高趋势,SIRT1表达降低,MMP-9表达增高,MCAO-48 h组与sham组比较差异最明显(P0.01)。结论:脑缺血后,伴随脑组织损伤的加剧,SIRT1和MMP-9信号通路的表达激活影响了AQP4的表达活化,共同参与了脑水肿的形成。     

CEPO经Mashl信号促进大鼠局部脑缺血后纹状体内神经发生

为检测氨甲酰化促红细胞叶三成素(CEPO)在大鼠脑缺血后发生过程中的作用及其相关信号通路,本实验将成年大鼠大脑中动脉栓塞(MCAO)后立即尾静脉给予CEPO(50μg/kg).结果显示:CEPO可显著降低大鼠MCAO后3 d梗塞面积,增加缺血侧神经于细胞增殖、促进神经干细胞分化成为神经元.CEPO的促神经发生效应与缺血侧纹状体内前神经元bHLH转录因子Mash1的表达上调密切相关.本结果提示CEPO对脑缺血具有神经保护作用,Mash1信号在缺血侧纹状体内可能介导CEPO增强的神经发生和神经元分化效应.