硒对沙土鼠脑缺血再灌注损伤后MDA、GSH-PX及细胞凋亡的影响

目的 研究亚硒酸钠对沙土鼠脑缺血再灌注损伤的保护作用及其机制。方法 将50只沙土鼠随机分为5组，Ⅰ组：假手术组；Ⅱ组：缺血再灌注1天处死组；Ⅲ组：缺血再灌注4天处死组；Ⅳ组：硒处理、缺血再灌注1天处死组；Ⅴ组：硒处理、缺血再灌注4天处死组。采用夹闭双侧颈动脉法制备沙土鼠脑缺血再灌注模型，焦油紫染色，光镜下观察各组海马CAl区神经细胞的形态变化，TUNEL染色观察神经细胞凋亡情况，计算凋亡密度。同时测定脑组织中丙二醛(MDA)、谷胱甘肽过氧化酶(GSH-PX)的含量。结果硒处理组沙土鼠缺血再灌注后，光镜下病理形态损伤较轻，凋亡密度较小，GSH-PX含量较高。结论 硒对沙土鼠脑缺血再灌注损伤具有保护作用，其机制可能与增强脑缺血再灌注早期脑组织中GSH-PX的活性，抑制氧自由基损伤，减轻脂质过氧化反应，而减轻缺血再灌注后细胞的坏死和凋亡有关。     

大鼠脑缺血再灌流后海马区一氧化氮合酶活性的变化

目的 :观察鼠全脑缺血再灌流后海马区NOS活性的变化。方法 :采用大鼠 4血管关闭方法制作全脑缺血再灌流模型。实验动物分为假手术组、缺血 10min组、再灌注 1、2、3d组 ,测定脑缺血再灌流后海马区NOS活性的变化。结果 :全脑缺血再灌注后海马组织NOS活性被激活上调。结论 :NO可能参与了海马CA1区迟发性神经元死亡 (DND)的发生。     

阿司匹林对沙土鼠全脑缺血-再灌注后脑内一氧化氮合酶及一氧化氮的影响

目的观察阿司匹林对沙土鼠全脑缺血-再灌注后的脑保护作用及其与脑内一氧化氮合酶及一氧化氮水平变化的关系。方法采用夹闭双侧颈总动脉的方法,制备沙土鼠短暂性全脑缺血-再灌注模型。27只健康雄性蒙古沙土鼠随机分为假手术组、脑缺血-再灌注组和阿司匹林治疗组,观察缺血7min再灌注24h后沙土鼠脑组织的病理学改变,以及一氧化氮合酶与一氧化氮水平的变化。结果病理学检查结果显示,沙土鼠脑缺血7min再灌注24h后海马CA1区缺血性损害明显,脑组织内一氧化氮合酶及一氧化氮水平显著升高(P<0.01);与脑缺血-再灌注组相比,阿司匹林治疗组沙土鼠的病理损害较轻,一氧化氮合酶与一氧化氮水平明显下降(P<0.01)。结论阿司匹林可显著减轻脑缺血-再灌注后的脑损伤,其作用机制可能与抑制一氧化氮合酶与一氧化氮水平上升有关。     

尼莫地平对大鼠急性脑缺血再灌注损伤早期保护作用的研究

目的探讨尼莫地平对急性脑缺血再灌注损伤的早期保护作用。方法线栓法复制大鼠急性脑缺血模型。30只雄性Wistar大鼠随机分为假手术、模型、尼莫地平3组。模型组采取缺血2h再灌注2h。尼莫地平组大鼠在缺血0时刻起每小时腹腔注射给药一次,剂量为5mg/kg。各组大鼠在手术4h后实验结束后,行腹主动脉采血,同时取完整脑组织。脑组织切片进行TTC染色,并比较各组脑组织梗死面积。检测各组大鼠血清及脑组织匀浆中SOD、MDA、NO含量。结果与模型组相比,尼莫地平组大鼠脑组织梗死面积显著减少。血清生化指标显示,模型组SOD含量显著低于假手术组,给予尼莫地平治疗后,SOD含量增加明显。模型组MDA、NO含量明显高于假手术组,尼莫地平组明显降低血清中MDA、NO。结论尼莫地平对大鼠急性脑缺血再灌注损伤有保护作用,这种保护作用与NO和氧化应激密切相关。     

妥泰对沙土鼠脑缺血再灌注损伤保护作用的实验研究

目的 研究妥泰对沙土鼠脑缺血再灌注损伤的保护作用及作用机制。方法 采用沙土鼠双侧颈总动脉结扎制成的全脑缺血模型。56只沙土鼠随机分为假手术组、缺血组、治疗组和预防组。预防组的动物分别给予大、小剂量的妥泰(100 mg/kg、50mg/kg)灌胃观察3天而行手术,术后24小时处死动物;治疗组的动物术后立即分别给于大、小剂量的妥泰(100 mg/kg、50mg/kg)灌胃观察7天处死动物。测定各组沙土鼠血、脑组织中的MDA、SOD的含量。光镜和电镜下观察脑组织CA_1区的病理及超微结构改变。结果 与缺血组相比,妥泰治疗组和妥泰预防组脑组织中的MDA含量明显降低(P<0.01),而SOD含量明显增高(P<0.01)。光镜和电镜下观察发现,妥泰治疗组和妥泰预防组的脑CA_1区缺血改变较缺血组减轻,且大剂量组缺血改变明显减轻。结论 妥泰对沙土鼠脑缺血再灌注损伤具有良好的保护作用,且保护作用与妥泰的剂量大小有关。其脑保护作用机制之一为妥泰能有效抑制氧自由基的产生及毒性。     

西比灵对鼠脑缺血再灌注损伤模型的血清及脑组织中SOD、MDA、N0、NOS含量及病理学的影响

目的 研究西比灵对鼠脑缺血再灌注损伤模型的血清及脑组织中超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)、一氧化氮合酶(NOS)的含量及病理学改变的影响。方法 选用21只沙土鼠并随机分为3组,脑缺血再灌注组(再灌注组)、西比灵预防组(预防组)及对照组,每组7只,分别测定血清、脑组织中SOD、MDA、NO、NOS的含量,并用电镜检测其病理学的变化。结果 与对照组比较,再灌注组显示严重的病理损害,其血清、脑组织中MDA、N0、NOS含量明显上升、SOD含量明显下降,两组比较有显著性差异(均P<0.01);与再灌注组比,预防组病理改变较轻,其血清、脑组织中MDA、NO、NOS明显下降,SOD明显上升,两组比较均有显著性差异(分别P<0.01和P<0.05)。结论 西比灵可减少自由基,诱导SOD生成,具有保护脑细胞的作用。     

MLK3介导的腺病毒表达谷氨酸受体羧基肽段对大鼠缺血性脑损伤的保护作用

目的 探讨大鼠脑缺血再灌注后腺病毒表达谷氨酸受体羧基肽段对海马CA_1区神经元的保护和MLK3表达的影响.方法 将SD大鼠随机分为假手术组、缺血再灌注对照组、表达病毒处理组、非表达病毒处理组及溶剂组.采用焦油紫染色、免疫印迹检测大鼠缺血再灌注后海马神经元损伤和脑组织MLK3表达的情况.结果 表达病毒处理组与缺血再灌注对照组、空载病毒处理组及溶剂组相比,海马CA_1区神经元损伤明显减轻,脑组织MLK3表达明显降低(P<0.05).结论 腺病毒表达谷氨酸受体羧基肽段可能通过降低脑组织中MLK3的表达对海马CA_1区神经元起保护作用.     

β-七叶皂甙钠对脑缺血-再灌注损伤大鼠自由基的影响

目的探讨β-七叶皂甙钠在大鼠脑缺血-再灌注损伤时对自由基的影响。方法用Wistar大鼠45只制备局灶性脑缺血-再灌注模型,分为假手术组、缺血-再灌注组、β-七叶皂甙钠治疗组,每个组又分为缺血2 h后再灌注6 h、12 h、24 h三个时间点,每组每个时间点5只大鼠,术后观察脑组织梗死面积、大鼠的神经行为学变化评分、脑组织超微病理结构变化、脑组织TTC染色,对缺血区脑组织超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondiadehyde,MDA)含量进行测定和分析。结果假手术组相应时间点神经功能损害评分显著低于缺血-再灌注组和治疗组(P<0.05),治疗组SOD含量明显高于缺血-再灌注组各时间点(P<0.05)。光镜显示假手术组脑组织结构未见明显病理改变,脑缺血-再灌注组神经细胞缺血坏死,细胞水肿明显,胶质细胞弥漫增生,炎性细胞浸润。结论自由基参与了脑缺血-再灌注损伤,β-七叶皂甙钠可降低缺血-再灌注后脑组织中MDA的含量,增加SOD的活性,减轻梗死体积,显著减轻大鼠神经功能损害和脑组织水肿,对局灶性脑缺血-再灌注损伤具有一定的保护作用。     

疏血通对局灶性脑缺血大鼠神经保护和hsp70表达水平的影响

目的 探讨疏血通对脑缺血-再灌注后神经保护作用的机制,拟为临床应用提供理论依据.方法 90只健康雄性SD大鼠,随机分为假手术组、缺血-再灌注组和疏血通治疗组,建立大脑中动脉闭塞模型.采用神经功能缺损评分对人鼠神经功能缺损程度进行评价,HE染色、TUNEL染色和免疫组织化学染色检测大鼠脑组织梗死灶体积、细胞凋亡及hsp70表达水平.结果 经疏血通治疗后,大鼠神经功能缺损程度明显改善,除再灌注后6h,其余各时间点疏血通治疗组评分均优于缺血-再灌注组(P<0.05).疏血通治疗组大鼠梗死灶体积明显缩小(P<0.01).再灌注后6 h,缺血半暗带区和海马区即可见凋亡细胞,分别于再灌注后48 h和72 h达峰值水平,疏血通治疗组表达高峰时间延迟,且各时间点凋亡细胞数目均少于缺血-再灌注组(P<0.05).再灌注后6 h,缺血半暗带区和大脑皮质即可见少量hsp70表达阳性细胞,两组均于再灌注后24 h达峰值水平,但疏血通治疗组各时间点hsp表达水平均高于缺血-再灌注组(P<0.05).结论 疏血通通过上调脑组织hsp70表达水平,减轻脑缺血-再灌注损伤,从而使梗死灶体积缩小、神经功能改善.     

西比灵对鼠脑缺血再灌注损伤模型的血清及脑组织中SOD、MDA、NO、NOS含量及病理学的影响

目的研究西比灵对鼠脑缺血再灌注损伤模型的血清及脑组织中超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)、一氧化氮合酶(NOS)的含量及病理学改变的影响.方法选用21只沙土鼠并随机分为3组,脑缺血再灌注组(再灌注组)、西比灵预防组(预防组)及对照组,每组7只,分别测定血清、脑组织中SOD、MDA、NO、NOS的含量,并用电镜检测其病理学的变化.结果与对照组比较,再灌注组显示严重的病理损害,其血清、脑组织中MDA、NO、NOS含量明显上升、SOD含量明显下降,两组比较有显著性差异(均P<0.01);与再灌注组比,预防组病理改变较轻,其血清、脑组织中MDA、NO、NOS明显下降,SOD明显上升,两组比较均有显著性差异(分别P<0.01和P<0.05).结论西比灵可减少自由基,诱导SOD生成,具有保护脑细胞的作用.     

The effects of Shuxuetong on the pathology of cerebral ischemia-reperfusion injury and GABA and TNF-α expression in gerbil models

Objective To study the protective effect and mechanism of Shuxuetong on gerbil brain tissue from the area of ischemia-reperfusion. Methods Cerebral ischemia-reperfusion animal model by transient clipping bilateral common carotid arteries in gerbils. Pathological changes in the hippocampal tissue were observed at different reperfusion time （12 h, 3 d, 7 d）. The expression levels of GABA and TNF-α in the hippocampal CA1 subfield were observed using immunohistochemitry at 12 h, 3 d after reperfusion. The difference of above indices among false operation group, ischemia-reperfusion group and treatment group were compared. Results The injuries of pathology to hippocampal area in ischemia-reperfusion group were more serious than treatment group. The expression levels of GABA in treatment group were significantly increased compared with ischemia-reperfusion group, but the expression levels of TNF-α between the two groups have no difference. Conclusion Shuxuetong has protective effect on brain tissue of ischemia-reperfusion by enhancing the expression of GABA in the hippocampal tissue.     

Fluorometric assay of nitrite and nitrate in brain tissue after traumatic brain injury and cerebral ischemia

Nitric oxide synthase (NOS) is distributed within the brain, and nitric oxide (NO) is felt to be involved in the pathophysiology of deterioration after head injury and cerebral ischemia. This study determined the levels of the stable end products of NOS (NO_x=nitrite+nitrate) after traumatic brain injury (TBI) and transient cerebral ischemia. A fluorometric assay using nitrate reductase and the NADPH regenerating system was used to quantitate NO_x in ultrafiltered (10-kDa cutoff) cortical and hippocampal extracts after reduction of nitrate. In TBI rats, both the plasma and tissue showed a sharp increase in NO_x levels 5 min after injury. Plasma NO_x returned to control levels by 2 h after injury. Ipsilateral-cortex NO_x levels returned to control levels 6 h after injury and remained constant from 6–24 h. Contralateral-cortex returned near to control levels after 1 h. Hippocampus also followed a similar trend. In gerbils, there was a significant elevation in tissue NO_x levels immediately after 10 min transient cerebral ischemia, which gradually returned to control levels over 24 h reperfusion. This striking burst of NO synthesis immediately after injury is clearly evident whether the injury is head trauma or ischemia, or whether the measurements were performed on tissue or plasma. It is unknown whether endothelial NOS, neuronal NOS, or both caused the elevation of the NO end products seen after the CNS insults.     

阿司匹林对沙土鼠脑缺血-再灌注损伤后细胞间黏附分子及降钙素基因相关肽表达的影响

目的 探讨阿司匹林对沙土鼠全前脑缺血-再灌注损伤后的脑保护作用及其对细胞间黏附分子及降钙素基因相关肽表达的影响。方法 采用夹闭双侧颈总动脉的方法，制备沙土鼠短暂性全前脑缺血-再灌注模型。63只沙土鼠随机分为假手术组、脑缺血-再灌注组（脑缺血组）和阿司匹林干预组（阿司匹林组）。应用免疫组化SABC法检测脑缺血-再灌注后细胞间黏附分子及降钙素基因相关肽表达水平的变化，以及阿司匹林干预对二者表达的影响。结果 （1）细胞间黏附分子表达的变化：脑缺血-再灌注24h，脑缺血组动物脑组织细胞间黏附分子的表达水平开始增加，3d后明显增强，至7d后仍维持在较高水平，与假手术组相比差异有显著性意义（P〈0．05）。而阿司匹林组动物细胞间黏附分子的表达水平在所有观察时限均明显低于脑缺血组，差异有显著性意义（P〈0．05）。（2）降钙素基因相关肽表达的变化：在脑缺血-再灌注后各时限，脑缺血组动物降钙素基因相关肽的表达均呈弱阳性；而阿司匹林组表达则呈强阳性。结论 脑缺血-再灌注可诱导细胞间黏附分子的表达上调，并抑制降钙素基因相关肽的表达。阿司匹林通过抑制细胞间黏附分子的表达水平和增强降钙素基因相关肽表达而获得较好的脑保护作用。     

EGb761对大鼠局灶性脑缺血再灌注损伤的保护作用

目的 :观察 EGb76 1对大鼠局灶性脑缺血再灌注损伤的保护作用。方法 :45只大鼠随机分为假手术组 (A组 ) ,脑缺血再灌注损伤组 (B组 ) ,EGb76 1治疗组 (C组 ) ,每组 15只。以线栓法制作大鼠脑缺血再灌注损伤模型。每组 10只缺血 6 0 min再灌注 6 0 min后断头处死 ,取脑测定 NO、NOS、MDA和 SOD变化 ,其余 5只缺血 3h再灌注 2 4h后断头处死 ,观察常规病理、Niss小体及凋亡细胞变化。C组于实验前 3天开始灌胃给 EGb76 1(15 0 mg/ kg,每日 2次 ,术前 1h、术后 12 h灌 EGb76 115 0 mg/ kg)。结果 :脑缺血再灌注后 ,B组 NO、MDA含量 ,NOS活性较 A组升高 ,SOD活性降低 (P<0 .0 5 ) ,病理变化明显 ,凋亡细胞增多。C组 NO、MDA含量及 NOS活性降低 ,SOD活性升高 (P<0 .0 5 ) ,C组病理变化减轻 ,凋亡细胞减少 (P<0 .0 5 )。结论 :EGb76 1对大鼠局灶性脑缺血再灌注损伤具有保护作用。     

甘草总黄酮对大鼠局灶性脑缺血再灌注损害的脑保护作用

目的　研究甘草总黄酮对大鼠局灶性脑缺血再灌注损害的脑保护作用。方法　我们拟采用线栓法建立的大鼠大脑中动脉 (MCA)缺血再灌注模型 ,并用 3种不同剂量的甘草总黄酮灌服后 ,测定缺血 2h再灌注 2 4h时血清和脑组织中丙二醛 (MDA)、超氧化物歧化酶 (SOD)、一氧化氮 (NO)、一氧化氮合酶 (NOS)活性。结果　发现甘草总黄酮能促进大鼠MCA、缺血再灌注 2 4h后神经功能恢复 ,甘草总黄酮能明显降低血清、脑组织中的MDA、NO含量 ,提高体内SOD的活性。结论　提示中药甘草总黄酮有抗氧化作用     

一氧化氮合酶抑制剂对缺血性海马迟发性神经元死亡的保护作用

目的：研究一氧化氮在缺血性海马迟发性神经元死亡中的作用,观察非选择性一氧化氮合酶抑制剂Ｎ＾Ｇ－ｎｉｔｒｏ－Ｌ－ａｒｇｉｎｉｎｅ对缺血性海马ＤＮＤ的影响。方法：实验分为假手术组,生理盐水治疗组,Ｌ－ＮＮＡ治疗组。采用大鼠４血管关闭方法制作了全脑缺血再灌流模型,以假手术组为对照,检测了脑缺血１０ｍｉｎ再灌流７２ｈ海马区ＮＯＳ活性的变化并观察计量了海马ＣＡ１区组织病理改变;     

The effect of ischemic post-conditioning on hippocampal cell apoptosis following global brain ischemia in rats

We evaluated the effect of brain ischemic post-conditioning on cell apoptosis in the hippocampus following global brain ischemia in rats. Adult male Sprague-Dawley rats were randomly divided into three groups (n=15/group): sham operation, ischemia/reperfusion (I/R) and ischemic post-conditioning (I PostC). Global brain ischemia was induced by four-vessel occlusion. Ischemic post-conditioning consisted of six cycles of 10s/10s reperfusion/reocclusion at the onset of reperfusion. All rats were sacrificed 24 hours or 72 hours after reperfusion. The hippocampal CA1 regions were analysed using the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end-labelling (Tunel) staining technique for determining cell apoptosis. Levels of caspase-3 and Bcl-2 were measured by Western blotting. After 72 hours, fewer Tunel-positive brain cells were observed in rats from the I PostC group than in rats from the I/R group (10.3 ± 2.7% versus 40.8 ± 6.2%, p<0.01). After reperfusion at 24 hours and 72 hours, expression of caspase-3 in the I PostC group was significantly decreased (p<0.01) and expression of Bcl-2 in the I PostC group was significantly increased (p<0.01) compared with the I/R group. We conclude that down-regulation of caspase-3 and up-regulation of Bcl-2 by ischemic post-conditioning may underlie the protective effects of post-conditioning.     

Effects of tetrahydrobiopterin on cerebral infarction after transient focal ischemia in rats

Abstract

Objectives: The present study investigated the effects of tetrahydrobiopterin (BH4) on cerebral infarction after transient focal ischemia in rats.

Methods: Focal ischemia (1·5 hours) was created in male Sprague-Dawley rats (250-280 g) by middle cerebral artery occlusion. Some rats were treated with 20 mg/kg tetrahydrobiopterin by intraperitoneal injection 30 minutes before reperfusion. At 2, 6, and 12 hours of reperfusion, the brains were harvested for the nitric oxide synthase (NOS) activity and nitric oxide (NO) level assays. At 12 hours of reperfusion, the brains were harvested for infarct size measurement.

Results: NOS activity and NO level were all augmented after reperfusion. BH4 treatment significantly further increased NOS activity and NO level. Cerebral infarct size was significantly bigger in BH4 treatment group compared to that in no treatment group.

Conclusions: The data indicate that BH4 enhances cerebral infarction after transient focal ischemia in rats, through NOS and NO pathway.