亚硒酸钠对沙土鼠海马CA1区神经元缺血/再灌注损伤的影响

目的探讨亚硒酸钠对沙土鼠海马CA1区神经元缺血/再灌注损伤的影响。方法采用夹闭双侧颈动脉法制备沙土鼠前脑缺血/再灌注模型,双重染色,电镜下观察各组海马CA1区神经元的超微结构变化。TUNEL染色光镜下观察和计数凋亡神经元,计算凋亡密度。结果硒处理组沙土鼠脑缺血/再灌注后,神经元超微结构的病理形态损伤减轻,凋亡细胞减少,与对照组比较差异有显著性(P<0.01)。结论亚硒酸钠对沙土鼠脑缺血/再灌注损伤的海马CA1区神经元超微结构及凋亡细胞具有保护作用。     

亚低温对沙土鼠前脑缺血再灌注海马神经元凋亡及p38活性的影响

目的通过动态观察亚低温(33℃,4h)对沙土鼠前脑缺血再灌注后不同时间点海马神经元凋亡细胞及磷酸化p38表达的影响,探讨亚低温脑保护的可能机制。方法采用沙土鼠双侧颈总动脉阻断5min前脑缺血再灌注损伤模型,随机分为假手术组,常温再灌注组,低温假手术组,低温再灌注组。每组根据再灌注的不同时间点(2h、4h、d1、3、d5)又分为5个对应的亚组(n=6)。在预定时间点行开阔法迷宫检查,TUNEL法检测海马CA1/3区的凋亡细胞,免疫组化检测pp38在海马各区的动态变化。结果4h亚低温可显著减少缺血沙土鼠d1、d3、d5的探索活动及CA1/区的凋亡细胞,明显抑制脑缺血后海马CA1区pp38早期的表达(2h、4h)。结论4h亚低温治疗对沙土鼠5min前脑缺血有明确的保护作用,抑制海马CA1区缺血再灌注早期pp38的激活可能是其减少海马细胞凋亡、产生脑保护作用的机制之一。     

亚低温对沙土鼠前脑缺血/再灌注海马CA1区神经元凋亡及Bcl-2、Caspase-3表达的影响

目的通过动态观察亚低温(33℃,4h)对沙土鼠前脑缺血/再灌注后不同时间点海马CA1区Bcl-2、Caspase-3的表达及凋亡细胞的影响,探讨亚低温脑保护的可能机制。方法采用沙土鼠双侧颈总动脉阻断5min前脑缺血/再灌注损伤模型,随机分为假手术组,常温再灌注组,低温假手术组,低温再灌注组,每组根据再灌注的不同时间点(2h、4h、1d、3d、5d)又分为5个对应的亚组(n=6)。在预定时间点行开阔法迷宫检查,TUNEL法检测海马CA1区的凋亡细胞,HE染色检测海马存活细胞,免疫组化检测Bcl-2、Caspase-3在海马各区的动态变化。结果4h亚低温可减少缺血沙土鼠1、3、5d的探索活动及CA1区的凋亡细胞,增加存活细胞,明显抑制脑缺血后海马CA1区Caspase-3早期的表达(2、4h),但对Bcl-2的表达没有影响。结论4h亚低温对沙土鼠5min前脑缺血有确切的保护作用,对Bcl-2的表达没有影响,抑制海马CA1区缺血/再灌注早期Caspase-3的激活可能是其减少海马细胞凋亡,产生脑保护作用的机制之一。     

银杏叶提取物对沙土鼠脑缺血再灌注损伤的影响

目的 :研究银杏叶提取物对沙土鼠脑缺血再灌注损伤的影响。方法 :采用夹闭沙土鼠双侧颈总动脉 10min或 2 0min再灌注 5d或 1d ,造成沙土鼠前脑缺血再灌注损伤模型。 95只动物分为假手术组、缺血再灌注组、银杏叶提取物 (GbE) 50mg·kg 1组及GbE10 0mg·kg 1组。于缺血前 2d和再灌注期间ig给药 ,观察GbE对脑组织钙、钠、水含量和脂质过氧化物的影响 ,以及对海马CA1区神经元迟发性死亡的保护作用。结果 :GbE能降低沙土鼠缺血再灌注后大脑皮层含水量 ,减轻钙、钠积累 ,且具有剂量效应相关性 ;GbE10 0mg·kg 1能降低缺血再灌注 1d内动物的死亡数及脑组织丙二醛含量 ,增加脑缺血后海马CA1区神经元密度。结论 :GbE对脑缺血再灌注损伤有保护作用。     

联合应用巴曲酶和依达拉奉对沙土鼠缺血再灌注后神经元凋亡的影响

探讨联合应用巴曲酶和依达拉奉对沙土鼠缺血再灌注后海马CA1区神经元凋亡的影响。以阻断沙土鼠双侧颈总动脉5min造成前脑完全缺血再灌注模型,并将其随机分为假手术组、对照组、巴曲酶组、联合治疗组。在不同时间点分别腹腔注射生理盐水、巴曲酶、巴曲酶和依达拉奉后,用原位末端标记法染色以及电镜下观察沙土鼠海马CA1区凋亡细胞,并在光镜下计算海马CA1区的神经元凋亡率。联合使用巴曲酶和依达拉奉后海马CAl区细胞凋亡率明显减少,与对照组及巴曲酶组比较P<0.05;海马CAl区细胞凋亡率在巴曲酶组0～24h时间点之间比较P>0.05,在0～24h时间点与48～72h时间点比较P<0.05;海马CAl区细胞凋亡率在联合治疗组0～48h时间点之间比较P>0.05;在0～48h时间点与72h时间点比较P<0.05。电镜下显示对照组海马CA1区锥体细胞的线粒体肿胀,胞核固缩,核形态异常。巴曲酶组的海马锥体细胞病变较对照组轻。联合治疗组海马锥体细胞病变较巴曲酶组更轻。联合应用巴曲酶和依达拉奉较单独使用巴曲酶可明显减少脑缺血再灌注后神经元细胞的凋亡。而且在48h内仍有较好的脑保护作用。     

SB202190减轻沙土鼠海马CA1区脑缺血再灌注损伤的作用与磷酸化Caspase-3含量变化的关系

脑缺血后恢复脑血流是治疗脑缺血最关键的方法,但再灌注后可加重缺血脑组织的死亡,这种再灌注损伤主要以凋亡为主,因此减少缺血再灌注后神经元凋亡为重要的脑保护机制.有作者报道p38MAPK的激活是再灌注损伤引起凋亡的重要信号转导通路之一.p38MAPK特异性的抑制剂SB202190能否减轻脑缺血再灌注损伤,目前少有报道.研究已知Caspase家族,尤其是Caspase-3一旦被激活,细胞进入凋亡过程.因此本实验通过应用SB202190,观察其对缺血再灌注后沙土鼠行为学变化和海马CA1区p-Caspase-3含量、凋亡神经元数的影响.     

ERK和JNK通路在沙土鼠脑缺血预处理中的表达及作用

目的探讨ERK和JNK在沙土鼠脑缺血预处理中的表达及作用。方法采用沙土鼠前脑缺血再灌注损伤模型。随机分为假手术组(SH)、预处理对照组(IC)、预处理缺血组(IP)及脑缺血再灌注组(IR);各组根据再灌注15 m in、2 h、4h、6 h、1 d、3 d、5 d及7 d又分8个亚组。在预定时间点行开阔法行为学检查、TUNEL法海马CA1/3区凋亡细胞检测、免疫组织化学SP法测定p-ERK、p-JNK在海马区的变化。结果IP可减少沙土鼠探索活动及海马CA1区凋亡锥体细胞数量(vsIR,P<0.01)各组CA1区p-ERK无表达,IR组海马CA1区p-JNK表达较强,再灌后1d最为明显,IP可明显减弱CA1区p-JNK的表达(vsIR,P<0.01),明显增强CA3区p-ERK的表达(P<0.05,P<0.01)。结论脑缺血可导致ERK及JNK在海马各亚区的差异性表达。缺血预处理可能通过抑制CA1区JNK磷酸化、增强CA3区ERK活性而保护海马细胞。     

褪黑素对沙土鼠脑缺血再灌注损伤的保护作用

目的研究褪黑素(melatonin,MT)对沙土鼠脑缺血再灌注损伤的神经保护作用。方法用沙土鼠双侧颈总动脉结扎法建立全脑缺血再灌注损伤模型。用开场迷宫测试沙土鼠的定向运动活性的变化。用T迷宫测试沙土鼠的学习及工作记忆能力。光镜下观察缺血后d 7海马CA1区神经元组织形态学变化。结果缺血模型组沙土鼠定向运动活性较假手术组显著增高,学习及工作记忆能力降低。MT可降低沙土鼠的定向运动活性,提高沙土鼠的工作记忆能力;还可显著减轻海马CA1区锥体神经元的病理改变,且作用呈剂量依赖性。结论MT对沙土鼠全脑缺血再灌注损伤有保护作用。     

氯化锂对沙土鼠全脑缺血后神经细胞凋亡及相关基因表达的影响

目的观察氯化锂对沙土鼠全脑缺血时海马CA1区神经细胞凋亡及相关基因蛋白表达的影响。方法54只沙土鼠,随机分为假手术组（SH组）、缺血再灌注组（IR组）、氯化锂预处理组（LI组）,每组18只。依术后处死动物时间的不同,各组再分别分为1、3、7d亚组。采用免疫组化、TUNEL染色法观察海马CA1区肿瘤抑制基因p53蛋白、核因子-κB（NF-κB）的表达和细胞凋亡情况。结果（1）脑缺血再灌注后3、7d,LI组各亚组海马CA1区TUNEL阳性细胞明显少于相对应的IR各亚组（P〈0．01）;（2）脑缺血再灌注后1、3、7d,LI组各亚组p53蛋白的表达显著低于相对应的IR组各亚组（P〈0．01）。（3）脑缺血再灌注后3d,LI组NF-κB阳性细胞表达明显低于相对应的IR组（P〈0．01）。结论氯化锂预处理能显著减轻沙土鼠短暂全脑缺血后海马CA1区神经元凋亡;下调促凋亡基因p53蛋白及NF-κB蛋白的表达可能是氯化锂产生脑保护作用的机制之一。     

白藜芦醇预处理对局灶性脑缺血/再灌注大鼠海马CA1区神经元凋亡的保护作用和机制

目的探讨白藜芦醇(resveratrol,Res)预处理对局灶性脑缺血/再灌注大鼠海马CA1区神经元凋亡的保护作用及其机制。方法♂SD大鼠60只,随机分为假手术组(Sham)、缺血/再灌注组(I/R)、白藜芦醇预处理组(Res+I/R),每组20只。采用线栓法阻断大脑中动脉血供90 min,拔出栓线造成局部脑区缺血/再灌注损伤。Res+I/R组缺血前1 h腹腔注射白藜芦醇(30 mg·kg-1)。缺血/再灌注后第5天,TUNEL法原位标记海马CA1区凋亡的神经元细胞,免疫组化法检测海马CA1区PI3K、p-Akt及Caspase-3的表达。结果 TUNEL染色结果显示,与I/R组相比较,白藜芦醇预处理明显减少脑缺血/再灌注损伤所引起的大鼠海马CA1区神经元凋亡(P<0.05);免疫组织化学结果显示,与I/R组相比,白藜芦醇预处理使海马CA1区PI3K、p-Akt表达明显增多(P<0.05),Caspase-3表达明显减少(P<0.05)。结论缺血前1 h白藜芦醇预处理对局灶性脑缺血大鼠海马CA1区神经元凋亡具有保护作用,其主要作用机制可能是通过激活PI3K-Akt信号通路进而抑制凋亡相关蛋白Caspase-3的表达有关。     

A comparison of protective effects between L-histidine and hypothermia against ischemia-induced neuronal damage in gerbil hippocampus

An increase in the histamine concentration in the brain has been demonstrated to provide protective effects against ischemia/reperfusion brain injury. Since hypothermia and barbiturates are also regarded to protect ischemic brains, effects of postischemic treatments were compared in gerbils between mild hypothermia and intraperitoneal administration of L-histidine, a precursor of histamine. Furthermore, effects of thioperamide, a histamine H(3) receptor antagonist, were evaluated in histidine-treated gerbils after 60 days. Transient forebrain ischemia for 4 min at 37 degrees C provoked severe neuronal damage in the hippocampal CA1 pyramidal cells after 7 days. Postischemic hypothermia (33 degrees C) for 3 h under pentobarbital anesthesia alleviated neuronal death, and the number of preserved neurons was 77+/-56/mm (mean+/-S.D., n=14). The effect of L-histidine injected three times, immediately, 6 h, and 24 h after reperfusion (1,000 mg/kg, i.p., each), was more prominent than that of hypothermia, and the number of preserved neurons was 142+/-55/mm (n=14). When the histologic outcome was evaluated after 60 days, most neurons were damaged in both the hypothermic and histidine groups. The improvement of the histologic outcome was observed even after 60 days in animals injected with thioperamide, immediately and 6 h after reperfusion (5 mg/kg, s.c., each), with three injections of l-histidine. The number of preserved neurons was 133+/-88/mm (n=10), while that in the hypothermic group was 7+/-15 (n=10). Activation of the central histaminergic system provides beneficial effects against cerebral ischemia.     

JNK通路在缺血预处理诱导海马神经元保护中的作用

目的探讨JNK通路在缺血预处理诱导海马神经元保护中的作用。方法♂蒙古沙土鼠,随机分为假手术组(SH)、缺血/再灌注组(I/R)、缺血预处理组(IP)、Anisomy-cin组(AN)、Curcumin组(CU)、Anisomycin复合IP组(AP)、Curcumin复合IP组(CP)及溶剂对照组(VE),每组据再灌注15min、2、4、6h、1、3、5及7d又分8个亚组。预定时间点行TUNEL海马CA1区凋亡细胞检测、免疫组化SP法检测p-JNK及Jun蛋白在海马CA1区的表达变化。结果IP、CU及CP可减少海马CA1区凋亡锥体细胞数(vsI/R,P<0.01),减弱CA1区再灌注各点p-JNK及Jun蛋白的表达水平(vsIR,P<0.01),该效应CP组>IP组>CU组。AN增加CA1区凋亡锥体细胞数(vsIR,P<0.01),增强CA1区再灌后1d内各点p-JNK及再灌后1～7d各点Jun蛋白表达水平(vsIR,P<0.01)。AP部分抵消IP保护效应。结论JNK通路激活参与沙土鼠海马CA1区缺血性神经元凋亡,缺血预处理可通过抑制CA1区JNK磷酸化、减少Jun蛋白表达而保护海马细胞和功能。抑制JNK通路激活可发挥缺血预处理相似的保护作用。     

Therapeutic effects of stiripentol against ischemia-reperfusion injury in gerbils focusing on cognitive deficit,neuronal death,astrocyte damage and blood brain barrier leakage in the hippocampus

Stiripentol is an anti-epileptic drug for the treating of refractory status epilepticus. It has been reported that stiripentol can attenuate seizure severity and reduce seizure-induced neuronal damage in animal models of epilepsy. The objective of the present study was to investigate effects of post-treatment with stiripentol on cognitive deficit and neuronal damage in the cornu ammonis 1 (CA1) region of the hippocampus proper following transient ischemia in the forebrain of gerbils. To evaluate ischemia-induced cognitive impairments, passive avoidance test and 8-arm radial maze test were performed. It was found that post-treatment with stiripentol at 20 mg/kg, but not 10 or 15 mg/kg, reduced ischemia-induced memory impairment. Transient ischemia-induced neuronal death in the CA1 region was also significantly attenuated only by 20 mg/kg stiripentol treatment after transient ischemia. In addition, 20 mg/kg stiripentol treatment significantly decreased ischemia-induced astrocyte damage and immunoglobulin G leakage. In brief, stiripentol treatment after transient ischemia ameliorated transient ischemia-induced cognitive impairment in gerbils, showing that pyramidal neurons were protected and astrocyte damage and blood brain barrier leakage were significantly attenuated in the hippocampus. Results of this study suggest stiripentol can be developed as a candidate of therapeutic drug for ischemic stroke.     

Fructose-1,6-Bisphosphate fails to ameliorate delayed neuronal death in the CA1 area after transient forebrain ischaemia in gerbils

Fructose-1,6-bisphosphate has been shown to reduce ischaemic-induced brain damage in rabbits and gerbils. In view of these findings, we investigated the effects of fructose-1,6-bisphosphate on delayed neuronal death, following bilateral forebrain ischaemia, in the gerbil hippocampus at the fourth day of reperfusion. We subjected gerbils to bilateral forebrain ischaemia for 20 min. Fructose-1,6-bisphosphate was administered: intraperitoneally at a dose of 1 g/kg in saline 1 hr before the occlusion or at a dose of 1 g/kg 1 hr before the occlusion and every 24 hr for 3 days; or intraventricularly at a dose of 0.1 g/kg just after the carotid occlusion. No significant differences in the number of dying cells in the CA1 area were found between each group of treated animals when compared with controls. This study suggests that fructose-1,6-bisphosphate, administered according to these three different schedules, fails to ameliorate delayed neuronal death after 20 min of bilateral forebrain ischaemia in the CA1 area of the gerbil hippocampus.     

Protective effect of pifithrin-alpha on brain ischemic reperfusion injury induced by bilateral common carotid arteries occlusion in gerbils

Involvement of p53 has been implicated in apoptosis induced cell death in ischemic reperfusion injury. In the present study, we have investigated neuroprotective potential of pifithrin-alpha, a p53 inhibitor in bilateral common carotid arteries occlusion (5 min) model of global cerebral ischemia in Mongolian gerbils. Gerbils were treated with pifithrin-alpha 3 mg/kg, ip. 30 min prior to occlusion. There was a significant increase in neurological symptoms and locomotor activity in ischemic animals as compared with the sham-operated animals. Increase in neurological symptoms and locomotor activity was attenuated by pifithrin-alpha 3 mg/ kg, ip. Significant increase in the number of the surviving neurons in the hippocampal CA1 pyramidal region was observed in ischemic animals treated with pifithrin-alpha 3 mg/kg, ip. This study demonstrates the neuroprotective effect of pifithrin-alpha in global cerebral ischemia in gerbils.     

川芎嗪对沙鼠前脑缺血-再灌注损伤后学习记忆的影响

目的探讨川芎嗪对沙鼠前脑缺血-再灌注后学习记忆的影响及其机制。方法40只蒙古沙土鼠随机分为4组。假手术组、脑缺血组、对照组、川芎嗪治疗组,每组10只。阻断沙土鼠双侧颈总动脉造成前脑缺血模型,4-FFF（4-pellet taking test）旱路迷宫法对沙鼠前脑缺血-再灌注7d后的学习记忆功能进行评定,HE染色方法观察海马CA1区神经元形态变化,免疫组织化学法观察海马CA1区胶质纤维酸性蛋白（glial fibrillary acidic protein,GFAP）阳性星形胶质细胞的反应。结果假手术组未见坏死神经元,神经元密度（27．6±4．3）HS,脑缺血组中坏死神经元显著增多,神经元密度明显下将（6．8±1．7）HS（P〈0．05）;与脑缺血组比较,川芎嗪治疗组坏死神经元显著较少,神经元密度增加（16．9±2．6）HS（P〈0．05）。CA1区星形胶质细胞活性在脑缺血组中（7．7±1．8）HS明显高于假手术组（3．9±1．2）HS（P〈0．05）;与脑缺血组比较,川芎嗪治疗组星形胶质细胞活性进一步增强（P〈0．05）。4-PTT旱路迷宫实验显示。脑缺血组中沙鼠参照记忆指标和工作记忆指标与对照组有明显的差异（P〈0．05）;川芎嗪治疗组上述指标显著改善（P〈0．05）。结论川芎嗪能改善前脑缺血沙鼠的学习记忆能力,与其对星形胶质细胞活性调节有关。     

NVP-AAM077和Ro25-6981对全脑缺血小鼠海马神经元损伤及BDNF表达的影响

目的探讨N-甲基-D-天冬氨酸受体(NMDA)亚基NR2A和NR2B特异性拮抗剂对脑缺血/再灌注后海马CA1区神经元损伤的不同影响及其可能机制。方法制作三动脉阻断(3-VO)小鼠全脑缺血模型,小鼠随机分为假手术组、脑缺血/再灌注(I/R)对照组、NVP-AAM077(NVP)干预组和Ro25-6981(Ro)干预组;应用Fluoro-JadeB(F-JB)和Nissl染色检测海马神经元变性死亡和存活情况,Western blot对脑源性神经生长因子(BDNF)蛋白表达水平进行定量分析。结果①小鼠全脑缺血12min/再灌注3d后,海马CA1区出现选择性迟发性神经元死亡,NVP干预组增加了缺血所致的海马神经元死亡(P<0.05),而Ro干预组CA1区神经元存活数量明显多于缺血/再灌注组(P<0.01);②NVP干预能明显下调缺血/再灌注所致的海马组织BDNF蛋白表达升高(P<0.01),而Ro干预能明显上调BDNF蛋白的表达(P<0.05)。结论 NMDA受体亚基NR2A和NR2B在小鼠脑缺血/再灌注损伤中具有不同的作用,其机制可能与调节BDNF表达改变有关。     

Effect of mergocriptine on postischemic brain damages.

The effects of mergocriptine (2-methyl-a-ergocryptine; CBM36-733; CAS 81968-16-3) on ischemia-induced brain damages were studied using both a global and a focal ischemia model. First, immediately after 5 min of forebrain ischemia induced by ligation of the bilateral carotid arteries of Mongolian gerbils, the animals were intraperitoneally injected with 3 mg/kg or 10 mg/kg CBM36-733. Seven days after ischemia, perfusion-fixed brains were processed by conventional histology. The number of neurons per mm in the CA 1 pyramidal cell layer was calculated and they were labelled neuronal density. In the control group, the neuronal density was 69.7 +/- 7.2 (mean +/- SEM/mm), in the vehicle group and 3 mg/kg of CBM36-733 treated group, they were 12.2 +/- 4.4 and 11.6 +/- 5.1, respectively. The neuronal density in the 10 mg/kg of CBM36-733 treated group was 42.2 +/- 8.4. These data indicate that 10 mg/kg of CBM36-733 protects on the CA 1 neurons against ischemia induced delayed neuronal death. Second, the effect of long-term administration of 3 mg/kg CBM36-733 on focal brain ischemia of the rats was studied by measuring regional cerebral blood flow and glucose metabolism by autoradiograms. After 90 min of middle cerebral artery occlusion, the rats were intraperitoneally injected with 3 mg/kg of CBM36-733 every day for 2 weeks. There were no significant differences in cerebral blood flow and glucose metabolism between the treated group and the vehicle group.(ABSTRACT TRUNCATED AT 250 WORDS)