神经调节素治疗小鼠脑缺血再灌注损伤的机制(英)

目的：研究神经调节素-1β(NRG-1β)对小鼠脑缺血再灌注后神经行为功能、脑geng梗死体积、脑组织含水量、神经细胞凋亡以及胶质细胞水通道蛋白-4（AQP-4）表达的影响和神经保护作用机制。 方法:应用线栓法建立小鼠大脑中动脉闭塞再灌注（MCAO/R）模型,经颈内动脉微量注射NRG-1β(2 μg/kg) 干预治疗,Bederson法评价动物的神经行为功能,氯化三苯基四氮唑（TTC）染色观察脑梗死体积,干湿重法测定脑组织含水量,免疫荧光染色检测神经细胞凋亡,免疫组织化学检测AQP-4的表达。结果:脑缺血再灌注损伤后,动物均表现神经行为功能障碍,缺血侧出现脑梗塞病灶,脑组织含水量、神经细胞凋亡数量和胶质细胞AQP-4表达均高于假手术对照组。与MCAO/R组相比较,MCAO/R+NRG-1β治疗组缺血24h动物神经行为功能损伤明显改善、凋亡神经细胞数明显减少、脑梗塞体积显著缩小,P<0.05;但脑组织含水量和AQP-4表达与MCAO/R组比较无显著差异,P>0.05。缺血再灌注22 h、46 h和70 h组,上述5项指标较相应的MCAO/R组均有显著差异,P<0.05。结论:NRG-1β可能通过下调脑缺血再灌注损伤诱导的胶质细胞AQP-4表达和抑制细胞凋亡,以减轻脑水肿和缩小梗死体积,从而改善动物的神经行为功能。     

神经调节素对大鼠脑缺血再灌注损伤AQP-4及GFAP表达的影响

应用线栓法经颈外-颈内动脉插线建立大脑中动脉闭塞再灌注(MCAO/R)大鼠动物模型,经颈内动脉单剂量注射1.5%神经调节素-1β(NRG-1β,0.3μg/kg)干预治疗。用干湿重法、免疫组化、免疫荧光双标记法和免疫印迹法观察NRG-1β对大鼠脑缺血再灌注损伤水通道蛋白(AQP-4)及胶质纤维酸性蛋白(GFAP)表达的影响。结果显示:随着缺血时间延长,对照组脑组织含水量逐渐增加,NRG-1β治疗能减少MCAO/R后脑组织含水量,与对照组相比,缺血1.5～2.0h组存在显著性差异(P<0.05)。脑缺血再灌注损伤可诱导脑组织AQP-4及GFAP表达,且随着缺血缺氧时间的延长,AQP-4及GFAP蛋白的表达逐渐增加。尽管它们均在胶质细胞中表达,但在脑组织中的分布略有不同。NRG-1β治疗可以增加二者在脑中的表达水平,与对照组相比具有显著性差异(P<0.01)。以上结果提示,NRG-1β可能通过激活内在的保护机制,增强胶质细胞的活性,从而抑制MCAO/R早期脑水肿的形成过程,改善神经元的生存环境,进而干扰脑缺血再灌注损伤的病理生理过程,对缺血性脑损伤具有积极的保护作用。     

神经调节素-1β对小鼠脑缺血再灌注损伤的干预作用及可能的机制

目的 研究神经调节素-1β(NRG-1β)对小鼠脑缺血再灌注后神经行为功能,脑梗死体积,脑组织含水量,神经细胞凋亡以及胶质细胞水通道蛋白-4(AQP-4)表达的影响和神经保护的作用机制.方法 应用线栓法建立小鼠大脑中动脉闭塞再灌注(MCAO/R)模型,经颈内动脉微量注射NRG-1β(2μg/kg)干预治疗,Bederson法评价动物的神经行为功能;氯化三苯基四氮唑(TTC)染色,观察脑梗死体积;干湿重法测定脑组织含水量;免疫荧光染色检测神经细胞凋亡;免疫组织化学检测AQP-4的表达.结果 脑缺血再灌注损伤后,动物均表现神经行为功能障碍,缺血侧出现脑梗塞病灶,脑组织含水量、神经细胞凋亡数量和胶质细胞AQP-4表达均高于假手术组.与对照组相比较,NRG-1β治疗组缺血24h,动物神经行为功能损伤明显改善,凋亡神经细胞数明显减少,脑梗塞体积显著缩小(P<0.05);但脑组织含水量和AQP-4表达与对照组比较无显著性差异(P>0.05).缺血再灌注22h、46h和70h组,上述5项指标较相应的对照组均有显著性差异(P<0.05).结论 NRC-1β可能通过下调脑缺血再灌注损伤诱导的胶质细胞AQP-4表达和抑制细胞凋亡,减轻脑水肿和缩小梗死体积,从而改善动物的神经行为功能.     

肢体缺血后适应对小鼠脑缺血再灌注损伤的影响及机制

目的:建立小鼠脑缺血后进行短暂肢体缺血提高脑缺血耐受模型,确定肢体缺血后适应对脑缺血时程的影响及热休克蛋白70(HSP70)的作用,探讨肢体缺血后适应(LIPostC)对脑缺血/再灌注损伤抑制作用和机制。方法:复制小鼠大脑中动脉闭塞模型(MCAO),第1批实验将小鼠分为9组:假手术组、脑缺血/再灌注组(缺血时间分别0.5 h、1 h、1.5 h、2 h组),脑缺血/再灌注+短暂肢体缺血(LIPostC)组(0.5 h+LIPostC、1 h+LIPostC、1.5 h+LIPostC、2 h+LIPostC组)。分别观察小鼠运动行为变化;TTC染色测量脑梗死体积;HE染色观察脑组织损伤程度;TUNEL法检测神经元凋亡程度。第2批实验将小鼠随机分为4组:假手术组、脑缺血/再灌注组、MCAO+LIPostC组和MCAO+LIPostC+quercetin组(缺血时间为2 h)。术后24 h用Western blotting法检测脑皮质中HSP70蛋白表达和神经功能评分。结果:脑缺血时程影响小鼠运动行为和脑损伤程度,随脑缺血时间延长,小鼠的脑再灌注损伤程度加重,其行为缺陷和脑病理变化明显;缺血2 h组脑损伤程度比缺血1.5 h组和缺血1 h组严重(P0.05)。脑缺血后不同时间施加LIPostC显示不同程度的神经保护作用。LIPostC各组与相对应的I/R组比较,其脑再灌注损伤程度呈现不同程度减轻,行为学评分降低、脑梗死体积减小,脑皮质损伤减轻,TUNEL阳性凋亡细胞数目减少。脑缺血2 h再灌注损伤较重,但LIPostC仍具有明显的脑保护作用。以2 h脑缺血小鼠为模型进行机制研究,结果表明,LIPostC可提高缺血脑组织HSP70蛋白表达,改善神经功能,HSP70抑制剂quercetin可削弱LIPostC的这种脑保护作用。结论:LIPostC可抑制MCAO小鼠的脑缺血再灌注损伤,促进缺血脑区HSP70表达和改善神经功能。HSP70在LIPostC提高MCAO小鼠的脑缺血耐受机制中发挥重要作用。     

胡黄连苷Ⅱ对大鼠脑缺血再灌注损伤的干预作用

目的研究胡黄连苷Ⅱ对大鼠脑缺血再灌注损伤的神经保护作用。方法应用线栓法建立大鼠大脑中动脉闭塞再灌注(MCAO/R)模型,经尾静脉注射胡黄连苷Ⅱ(10mg/kg)和丹参素钠(10mg/kg)干预治疗,Bederson法评价动物的神经行为功能,氯化三苯基四氮唑(TTC)染色观察脑梗死体积,组织病理学观察神经细胞结构,原位缺口末端标记法(TUNEL)检测细胞凋亡。结果脑缺血再灌注损伤后,大鼠均表现神经行为功能障碍,缺血侧出现脑梗塞病灶,神经细胞凋亡数量均高于假手术组。胡黄连苷Ⅱ和丹参素钠治疗后,神经细胞凋亡数量明显减少、脑梗塞体积显著缩小,动物神经行为功能明显改善,与模型对照组比较均有显著性差异(P0.05)。胡黄连苷Ⅱ组脑梗塞体积显著小于丹参素钠组(P0.05)。结论胡黄连苷Ⅱ可能通过抑制细胞凋亡,缩小梗死体积而改善大鼠的神经行为功能。     

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。     

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。     

sCR1-SCR15-18蛋白减轻补体介导的大鼠脑缺血/再灌注损伤

目的: 探讨补体在大鼠大脑缺血/再灌注(ischemia-reperfusion,I/R)损伤中的作用及重组人可溶性补体受体Ⅰ型SCR15-18蛋白(sCR1-SCR15-18)的保护作用。方法: 75只雄性SD大鼠,随机分为假手术组、I/R组和sCR1 -SCR15-18保护组。采用线栓法建立大鼠大脑中动脉闭塞模型(middle cerebral artery occlusion MCAO),缺血2 h,再灌注24 h后,进行神经功能学评分,测定脑梗死体积、大脑皮质髓过氧化物酶(myeloperoxidase,MPO)活性,观察大脑皮质区补体C3b沉积和病理改变。结果: 缺血/再灌注24 h后,sCR1-SCR15-18保护组神经功能学评分,脑梗死体积及脑皮质MPO活性明显低于I/R组(P<0.05);sCR1 -SCR15-18保护组缺血脑组织补体C3b沉积明显减少,病理损伤减轻。结论: 补体在脑I/R损伤中起一定作用,sCR1-SCR15-18蛋白对大鼠I/R损伤脑具有保护作用。     

Neanthes japonica (Iznka) fibrinolytic enzyme reduced cerebral infarction,cerebral edema and increased antioxidation in rat models of focal cerebral ischemia

Thrombolytic agent is increasingly being used in treating acute ischemic stroke. A novel protease with strong thrombolytic activity, Neanthes japonica (Iznka) fibrinolytic enzyme (NJF) discovered in our laboratory has been reported with characteristics of direct hydrolyzing fibrin and fibrinogen. The neuroprotective effect of NJF and urokinase (UK) was tested in rat models of middle cerebral artery occlusion (MCAO). The model was successfully produced by introducing an intraluminal suture into the left middle cerebral artery (MCA). NJF (0.25, 0.5, 1 mg/kg) was injected intravenously 1 h after the onset of reperfusion. Compared with vehicle group, MCAO animals treated with NJF showed dose dependent reduction in cerebral infarction with improved neurological outcome. Meanwhile, ischemia induced cerebral edema was reduced in a dose dependent manner. Treatment with NJF at 0.5 mg/kg was almost equivalent to UK at 15,000 U/kg dosage in the reduction of cerebral infarction and cerebral edema. Biomedical assay showed that NJF treatment suppressed lipid peroxidation and restored superoxide dismutase (SOD) activities in brain tissue. These results suggest that NJF posses neuroprotective potential in rat MCAO and reperfusion model. Neuroprotection shown by NJF may be attributed to inhibition of lipid peroxidation, increase in endogenous antioxidant defense enzymes.     

Modulation of the balance between cannabinoid CB(1) and CB(2) receptor activation during cerebral ischemic/reperfusion injury

Cannabinoid receptor activation has been shown to modulate both neurotransmission (CB(1)) and neuroinflammatory (CB(2)) responses. There are conflicting reports in the literature describing the influence of cannabinoid receptor activation on ischemic/reperfusion injury. The goal of this study was to evaluate how changing the balance between CB(1) and CB(2) activation following cerebral ischemia influences outcome. CB(1) and CB(2) expression were tested at different times after transient middle cerebral artery occlusion (MCAO) in mice by real-time RT-PCR. Animals subjected to 1 h MCAO were randomly assigned to receive different treatments: a CB(1) antagonist, a CB(2) antagonist, a CB(2) agonist, a CB(1) antagonist plus CB(2) agonist, a CB(2) antagonist plus CB(2) agonist or an equal volume of vehicle as control. Cerebral blood flow was continuously monitored during ischemia; cerebral infarction and neurological deficit were tested 24 h after MCAO. Cerebral CB(1) and CB(2) mRNA expression undertook dynamic changes during cerebral ischemia. The selective CB(1) antagonist significantly decreased cerebral infarction by 47%; the selective CB(2) antagonist increased infarction by 26% after 1 h MCAO followed by 23 h reperfusion in mice. The most striking changes were obtained by combining a CB(1) antagonist with a CB(2) agonist. This combination elevated the cerebral blood flow during ischemia and reduced infarction by 75%. In conclusion, during cerebral ischemia/reperfusion injury, inhibition of CB(1) receptor activation is protective while inhibition of CB(2) receptor activation is detrimental. The greatest degree of neuroprotection was obtained by combining an inhibitor of CB(1) activation with an exogenous CB(2) agonist.     

Neuroprotective effects of berberine on stroke models in vitro and in vivo

Berberine is an alkaloid derived from herb medicine Coptidis Rhizom. Although there are increasing evidences that berberine exhibits neuroprotective effects against ischemic brain damage, little is known about the mechanism. In this study, we investigated the effect of berberine on ischemic injury in a middle cerebral artery occlusion (MCAO) model. We found that berberine improved neurological outcome and reduced ischemia/reperfusion (I/R)-induced cerebral infarction 48h after MCAO. The protective effect of berberine was confirmed in in vitro study. Berberine protected PC12 cells against oxygen-glucose deprivation (OGD)-induced injury. The results showed that berberine inhibited reactive oxygen species (ROS) generation, and subsequent release of pro-apoptotic factor cytochrome c and apoptosis-inducing factors (AIFs) evoked by OGD. Findings of this study suggest that berberine protects against ischemic brain injury by decreasing the intracellular ROS level and subsequently inhibiting mitochondrial apoptotic pathway.     

Intracerebroventricular injection of human prostatic acid phosphatase has potent neuroprotective effects against transient focal cerebral ischemia in rats

Though the potential use of adenosine as a neuroprotective agent has long been realized, there are currently no adenosine-based therapies for the prevention or treatment of cerebral ischemia and reperfusion injury. Prostatic acid phosphatase (PAP), an enzyme that has long served as a diagnostic marker for prostate cancer, has been recently demonstrated to exhibit ecto-5′-nucleotidase activity, and dephosphorylate endogenous extracellular AMP to adenosine. We therefore tested the hypothesis that PAP has sustained and potent neuroprotective effects against cerebral ischemia in the rat model of middle cerebral artery occlusion. We found that hPAP produced significant neuroprotection against focal cerebral ischemia, as evident from significant reduction in cerebral infarction and neurological deficits. The therapeutic time window for hPAP in rat focal cerebral ischemia model was limited from 6 h before ischemia to 1.5 h after reperfusion. The present study suggested that PAP is a potential candidate for the prevention and treatment of cerebral ischemic injury, especially during perioperative period.     

黄芪甲苷对脑缺血/再灌注损伤大鼠细胞自噬的影响

目的:探讨黄芪甲苷对脑缺血/再灌注损伤大鼠细胞自噬的影响。方法:选取清洁级雄性SD大鼠70只随机分为假手术组、脑缺血/再灌注组、溶剂对照组、黄芪甲苷组、黄芪甲苷+自噬抑制剂组、自噬抑制剂组和自噬激活剂组。采用线栓法建立大鼠局灶性脑缺血/再灌注损伤模型。观察大鼠神经缺损症状,根据Zea Longa评分标准挑选模型成功的大鼠;采用TTC染色法检测大鼠脑梗死体积;尼氏染色观察大鼠神经细胞形态学变化;透射电子显微镜观察细胞自噬现象;Western blot检测beclin-1和LC3-Ⅱ蛋白表达量的变化。结果:假手术组无神经缺损症状,未出现脑梗死灶,尼氏体丰富、染色均匀。与假手术组相比,脑缺血/再灌注组出现明显的脑梗死灶,神经细胞坏死增多,尼氏体数量减少、着色较浅,透射电镜下可见典型的自噬体,自噬标志蛋白beclin-1和LC3-Ⅱ表达增加(P 0. 05)。与脑缺血/再灌注组相比,黄芪甲苷组和自噬激活剂组可明显减小脑梗死体积,神经细胞有不同程度的恢复,尼氏体稍增多,自噬体数量、beclin-1和LC3-Ⅱ表达量均增加(P 0. 05);自噬抑制剂组脑梗死体积增大,神经细胞坏死严重,尼氏体减少,着色变浅,自噬体数量、beclin-1和LC3-Ⅱ表达量均减少(P 0. 05);溶剂对照组无明显变化。与黄芪甲苷组比较,黄芪甲苷+自噬抑制剂组和自噬抑制剂组脑梗死体积增加,神经细胞坏死增多,尼氏体数量减少,自噬体数量、beclin-1和LC3-Ⅱ表达量降低(P 0. 05)。结论:黄芪甲苷可通过激活自噬而减轻脑缺血/再灌注损伤,从而发挥神经保护作用。     

Bone marrow stromal cells can be delivered to the site of traumatic brain injury via intrathecal transplantation in rabbits

Bis(7)-tacrine, a promising anti-Alzheimer's dimer, has been shown to have multiple neuroprotective activities in vitro. Here, we investigate whether bis(7)-tacrine attenuates focal cerebral ischemic impairment in vivo. Cerebral ischemia was induced in Sprague-Dawley rats by transient (2h) middle cerebral artery occlusion (MCAO) followed by 24h of reperfusion. Bis(7)-tacrine administered intraperitoneally 15 min after ischemia dose-dependently improved neurological behavior deficits and reduced both cerebral infarct volume and edema. The TUNEL staining assay showed that bis(7)-tacrine attenuated neuronal apoptosis in the penumbral region. Compared with that for memantine, a moderately effective N-methyl-d-aspartate (NMDA) receptor antagonist with a similar affinity and potency to bis(7)-tacrine in blocking NMDA receptors, the therapeutic window for bis(7)-tacrine was wider and lasted up to 6h after the onset of ischemia. Bis(7)-tacrine did not affect physiological parameters or regional cerebral blood flow during either the occlusion period or the early reperfusion stage. In conclusion, bis(7)-tacrine dose- and time-dependently protected against acute focal cerebral ischemic insults, possibly through the drug's anti-apoptotic effects during multiple events in the ischemic cascade.     

人参皂甙Rb1阻止大鼠局灶性脑缺血细胞凋亡和诱导NAIP表达

人参皂甙Rb1(GRb1)是人参中一个最重要的有效成分(人参属五加科中一属),能减少大鼠暂时性脑缺血梗塞面积和改善神经功能缺失症状,这种神经保护作用的机制不完全清楚。本实验研究GRb1的神经保护作用是否与防止神经元凋亡和调控神经元凋亡抑制蛋白(NAIP)的表达有关。通过阻塞大鼠大脑中动脉建立局灶性脑缺血模型,再灌注开始后立即给予腹腔注射GRb1(40mg/kg)。具有神经功能缺失的大鼠被随机分成2组:缺血组和GRb1组,每个组根据再灌注时间(3h,12h,1d,2d,3d,5d,10d,n=4/每时间点)分为亚组。正常大鼠和假手术组做为对照组。TUNEL标记分析凋亡细胞,用免疫组织化学的方法检测NAIP的表达。结果显示再灌注3h凋亡细胞数量开始升高,24h达高峰,后下降,但再灌注10d的凋亡细胞数量显著高于对照组(P<0.01)。与缺血组相比,GRb1各亚组的凋亡细胞数减少,但再灌注12h至3d,其差异具有统计学意义。在对照组,NAIP弱或阴性的免疫反应广泛出现在脑实质神经元。再灌注3h,NAIP阳性细胞增加,12h时达高峰,后下降。再灌注5d,NAIP阳性细胞数量比对照组少(P<0.05)。NAIP阳性神经元出现缺血性改变如扇形或三角形,纹状体星形胶质细胞强表达NAIP。在GRb1组,NAIP阳性细胞数量从再灌注12h到10d,显著高于缺血组。本实验结果提示大鼠局灶性脑缺血时,GRb1能减少细胞凋亡,其机制可能与增加NAIP的表达有关。     

Zileuton Reduces Inflammatory Reaction and Brain Damage Following Permanent Cerebral Ischemia in Rats

5-Lipoxygenase inhibitor zileuton has been demonstrated to attenuate ischemic brain damage in rats of permanent focal cerebral ischemia in previous work. To further investigate the mechanism underlying zileuton's neuroprotection, adult male Sprague-Dawley rats underwent permanent middle cerebral artery occlusion (MCAO), then received treatment with zileuton or vehicle after the onset of ischemia. Neurological deficit, cerebral infarction, and morphological characteristic were measured 6 and 24 h after MCAO. The enzymatic activity of myeloperoxidase (MPO) was assessed 6 and 24 h after MCAO and the lipid peroxidation levels were evaluated by malondialdehyde assay. Expression of nuclear factor-kappa B (NF-κB) p65 in rat brain was detected by immunohistochemistry and Western blot. Expression of inducible nitric oxide synthase (iNOS) in rat brain was determined by RT-PCR and Western blot. Nitric oxide production in rat brain was also measured 24 h after MCAO. The concentration of TNF-α and IL-1β in serum were detected by ELISA. Zileuton significantly reduced neurological deficit scores, cerebral infarct volume, MPO activity, and the lipid peroxidation levels. It also inhibited the expression of NF-κB and decreased the expression and activity of iNOS in rat brain. In addition, zileuton attenuated the release of TNF-α and IL-1β in serum. Our results suggest that zileuton reduces inflammatory reaction and brain damage in a rat model of permanent focal cerebral ischemia. The neuroprotective effect of zileuton in cerebral ischemia might be associated with the inhibition of inflammatory reaction.     

丁苯酞预处理对脑缺血再灌注损伤大鼠神经功能缺损评分、氧化损伤和形态学的影响

目的探讨丁苯酞(NBP)预处理对脑缺血再灌注损伤大鼠神经功能缺损评分、氧化损伤和形态学的影响。方法 90只雄性SD大鼠随机分为假手术组(Sham)、模型组(IR)、NBP预处理低剂量组(NBPⅠ)、NBP预处理中剂量组(NBPⅡ)和NBP预处理高剂量组(NBPⅢ),每组18只,制造模型前7d开始灌胃给药,1次/d。线栓法制作大脑中动脉栓塞(MCAO)模型,缺血2h再灌注24h后进行神经功能缺损评分;2,3,-氯化三苯基四氮唑(TTC)染色观察脑组织梗死的情况;苏木素-伊红(HE)染色显微镜下观察脑组织形态学变化;采用羟胺法测定超氧化物歧化酶(SOD)活性,化学比色法测定谷胱甘肽过氧化物酶(GSH-PX)活性,硫代巴比妥酸(TBA)法测定丙二醛(MDA)含量。结果 (1)Sham组神经功能缺损评分为零,脑组织无梗死情况发生,神经元形态规则,脑组织中SOD、GSH-PX活性和MDA含量正常。(2)与IR组比较,NBP预处理各组大鼠神经功能评分显著降低(均P0.01),NBPⅠ、Ⅱ、Ⅲ组神经功能评分依次递减(均P0.05)。(3)与IR组比较,NBP预处理各组脑组织梗死体积依次减小(均P0.05),神经元损伤减轻。(4)NBP预处理各组脑组织中SOD、GSH-PX活性明显升高,MDA含量显著减少(P0.01);NBPⅠ、Ⅱ、Ⅲ组SOD、GSH-PX活性依次递增,MDA含量依次递减(均P0.05)。结论丁苯酞预处理可上调SOD、GSH-PX活性,降低MDA含量,减小脑梗死体积,减轻神经元损伤,发挥对脑缺血再灌注损伤大鼠的预防性保护作用。     

Upregulation of erbB receptors in rat brain after middle cerebral arterial occlusion

We have previously demonstrated that neuregulin-1 (NRG-1) is upregulated and is neuroprotective in ischemic brain injury, however the expression and localization of its receptors during ischemia has not been investigated. Therefore, we used a rat middle cerebral artery occlusion (MCAO) model to examine the distribution of erbB receptors following ischemic stroke. Like neuregulin-1, we observed a dramatic induction of erbB4 in the peri-infarct regions of the ipsilateral cortex 24 h following MCAO. Using Fluoro-Jade B (FJB) staining as a marker of neurodegeneration, erbB4 was upregulated in FJB-positive cells, suggesting that erbB receptors are induced in injured neurons. The increase in erbB receptors was seen in neurons and a subpopulation of macrophages/microglia. There was no erbB co-localization with GFAP-positive astrocytes. These results demonstrate that erbB receptors are upregulated in neurons and macrophages/microglia following ischemic stroke and may be involved in neuroprotection and repair.