大鼠大脑中动脉缺血和再灌注后环氧合酶-2mRNA表达的研究

目的研究大鼠大脑中动脉缺血和再灌注模型中环氧合酶－２（ＣＯＸ－２）基因的表达。方法原位杂交方法。结果缺血３０ｍｉｎ再灌注组,血流再通４ｈ后缺血区的大脑皮层有很强的表达并持续２４ｈ。缺血９０ｍｉｎ再灌注组和持续缺血组在缺血区以外的广泛大脑皮层显著表达,在海马的齿状回两侧及纹状体也发现表达。ＣＯＸ－２ｍＲＮＡ的表达可被ＭＫ－８０１抑制。而ＮＢＱＸ和倍他米松对其表达没有影响。结论在缺血区、缺血周边部、缺血远隔区有ＮＭＤＡ受体介导的ＣＯＸ－２表达,阐明上述区域花生四烯酸代谢活性化     

血红素氧合酶-1及血红素氧合酶-2在大鼠局灶性脑缺血中的意义

目的　研究血红素氧合酶 1(HO 1)及血红素氧合酶 2 (HO 2 )在局灶性脑缺血中的作用。方法　采用大鼠大脑中动脉栓塞脑缺血模型 ,对 6 6只大鼠脑缺血后不同时间点进行HO 1、HO 2免疫组化染色及病理学研究 ,并用计算机图像分析技术计算两者表达水平。结果　栓塞后 30min大鼠皮质及海马即有HO 1阳性神经元及胶质细胞的表达 ,且随着时间推移HO 1的表达逐渐增强 ,到栓塞后 12h达峰值 (P <0 0 1) ,以后逐渐下降 ,栓塞后 1周仍有HO 1表达。HO 2在正常大鼠及梗死大鼠脑组织内均有表达。栓塞后不同时间段 ,HO 2阳性神经元的数量无明显变化 (P >0 0 5 ) ,但HO 2表达呈动态变化 ,2 4h时最高 (P <0 0 1) ,以后逐渐下降。结论　脑缺血时脑内HO 1、HO 2表达的不同变化 ,是脑组织对损伤恢复重要的机制之一。HO 1修复受损的神经元和胶质细胞 ,而HO 2在于维护正常细胞的稳定     

局灶性脑缺血时血红素氧合酶-1 mRNA的表达

目的 观测永久性脑缺血后一氧化碳限速酶一血红素氧合酶-1(HO-1)mRNA表达的变化规律。方法 在建立MCAO局灶性脑缺血模型基础上，采用半定量RT-PCR技术观察并测定脑缺血后不同时相HO-1 mRNA的相对表达量。结果脑缺血后1h即有HO-1 mRNA的表达，随时间延长而逐渐升高，12h达最高，以后逐渐下降，至7d时仍有表达。结论 脑缺血后HO-1 mRNA表达变化是缺血脑组织损伤后重要的自身恢复机制之一。     

大鼠局灶性脑缺血后脑内HO-2蛋白的表达

目的 :研究局灶性脑缺血时脑内血红素氧合酶 2 (HO 2 )的表达。方法 :在大鼠大脑中动脉阻塞致脑缺血的不同时间点应用免疫组化、病理学及图像分析检测HO 2的表达。结果 :正常大鼠及实验大鼠的梗死侧与非梗死侧皮质、丘脑基底节区和海马齿状回均有HO 2阳性神经元。梗死灶内无表达。梗死后各时间段 ,HO 2阳性神经元的数量无明显变化 (P >0 0 5) ,而图像分析显示1 2～ 2 4h时达最高峰 (P <0 0 1 )。结论 :脑缺血时脑内神经元有HO 2蛋白阳性表达 ,其对脑保护作用的机制有待进一步研究     

大鼠短暂局灶性大脑中动脉缺血后calpain的表达

目的：研究calpain在缺血性脑损伤中的作用，进一步探讨缺血性脑血管病的分子机制，为治疗研发提供理论依据。方法：用Belayev改良的Langa线栓法制备大鼠局灶性大脑中动脉(MCA)缺血／再灌注模型，TTC染色观察梗死灶的形成，分别用原位杂交及免疫组化技术检测鼠脑中calpain mRNA与活性蛋白的表达。结果：缺血2h再灌注24h,TTC染色见明显的梗死灶形成，正常脑组织、假手术组及：MCAO缺血对侧脑中有少量的calpain mRNA表达，但活性蛋白几无表达；缺血脑组织calpain mRNA表达及蛋白质活化均显著增加，呈双峰式，MCA缺血2h增加，再灌注4h减少，至24h更明显增高，而48h又有所下降。结论：Calpain参与了缺血性脑损伤过程，尤其在迟发性神经元死亡中起重要作用。     

血管性痴呆大鼠海马区核因子-κB、环氧合酶-2的表达变化

目的 通过检测血管性痴呆(vascular dementia,VD)大鼠海马CA1区核因子-κBp65(nuclear factor-κB p65, NF-κBp65)与环氧合酶-2(cyclooxygenase-2,COX、2)的表达,探讨NF -κB和COX-2的损伤作用.方法 28只大鼠随机分为假手术组(SOG)13只和模型组(VD)15只,取海马CA1区为观察部位,HE染色观察锥体细胞的改变,免疫组化检测NF-κBp65、COX-2的表达.结果 与SOG相比,VD大鼠海马CA1区锥体细胞损伤、丧失明显,NF-κBp65、COX-2蛋白增加,差异有统计学意义(P﹤0.01).结论 VD大鼠海马CA1区NF-κBp65、COX-2蛋白的高表达可能是学习记忆障碍的原因之一.     

环氧合酶-2及其抑制剂在胶质瘤中的研究进展

环氧合酶(cyclooxygenase,COX)又名前列腺素内过氧化物合成酶,COX-2是其诱导型酶。胶质瘤中COX-2的高表达和病理分级、预后相关。COX-2具有促进肿瘤细胞增殖、抑制细胞凋亡、诱导胶质瘤血管生成及通过前列腺素抑制肿瘤免疫等作用。目前的研究也发现COX-2抑制剂特别是选择性抑制剂联合化疗药物抑制肿瘤的增殖以及联合放疗可以增强肿瘤的放射敏感性,临床试验未发现明显的毒副作用。COX-2抑制剂的应用可能是未来胶质瘤治疗的新途径。     

环氧合酶-2与PD关系研究进展

<正> 帕金森病(Parkinson disease,PD)是一种常见的神经系统变性疾病,以大量选择性的中脑黑质DA能神经元进行性变性环死和患者脑内出现Lewy小体为主要病理特点。研究发现几种突变基因如:α-synuclein和Parkin与大多数早发和家族性PD有关,然而,这些病例仅占PD发生率的很小部分,大多数散发PD的病因和引起神经元变性的准确机制不明。近年来已     

环氧合酶-1基因缺失阻断褪黑素对脑缺血的保护作用

目的探讨褪黑素对脑缺血的保护作用及环氧合酶-1(CPX-1)在其中的作用。方法应用光化学法对野生型及COX-1基因缺失纯合型小鼠诱导脑梗死,给予褪黑素(15 mg/kg)及0．9%氯化钠溶液进行治疗。术后第3 d应用TTC染色测量脑梗死体积,应用尼氏染色分别对缺血半暗带区存活神经元进行定量分析。结果(1)COX -1基因对脑梗死体积和缺血半暗带区神经元数目无影响;(2)褪黑素减小野生型小鼠组的脑梗死体积,增加海马区缺血半暗带内的神经元数目,但是对COX-1基因缺失的纯合型小鼠的脑梗死体积和缺血半暗带区的神经元数目无影响;(3)褪黑素治疗与COX-1基因对总梗死体积、皮层梗死体积和海马区缺血半暗带神经元数目有显著的交互影响。结论COX-1基因对光化学法所致的脑缺血无影响。褪黑素对野生型小鼠的脑保护作用随着COX-1基因缺失而消失,其神经保护作用通过或部分通过抑制COX-1实现。     

血管性痴呆大鼠海马区核因子-κB、环氧合酶-2的表达变化

目的通过检测血管性痴呆(vascular dementia,VD)大鼠海马CA1区核因子-κBp65(nuclear factor-κB p65,NF-κBp65)与环氧合酶-2(cyclooxygenase-2,COX-2)的表达,探讨NF-κB、COX-2对VD大鼠的损伤作用。方法28只大鼠随机分为两组,假手术(SOG)组(n=13)和模型(VD)组(n=15),采用HE染色,光镜下观察海马CA1区锥体细胞的改变,免疫组化方法检测海马CA1区NF-κBp65、COX-2蛋白的表达。结果与假手术组相比,模型组组海马CA1区锥体细胞损伤、丧失明显,NF-κBp65、COX-2蛋白表达高于假手术组,与假手术组相比有统计学意义(P(0.01)。结论血管性痴呆大鼠海马CA1区NF-κBp65、COX-2蛋白的表达增加,NF-κBp65、COX-2蛋白的高表达可能是学习记忆障碍的原因之一。     

Growth-associated protein GAP-43 detection in the neuronal somata following middle cerebral artery occlusion in the rat

Aabstract

We first detected growth-associated protein (GAP-43) immunoreactivity in the neuronal somata following middle cerebral artery occlusion in the rat. Four days after the middle cerebral artery occlusion, GAP-Lt.3 immunoreactivity was detected in some cortical neurons of the ischemic penumbra at the level of the hippocampus. [Neural Res 1997; 19: 160–164]     

Effect of the kappa-1 opioid agonist CI-977 on ischemic brain damage and cerebral blood flow after middle cerebral artery occlusion in the rat

The effects of the kappa-1 opioid agonist CI-977 upon the volume of ischemic brain damage (defined using quantitative neuropathology) and local cerebral blood flow (CBF) (defined using quantitative [¹⁴C]iodoantipyrine autoradiography) have been examined at 4 h and 30 min, respectively, after permanent middle cerebral artery (MCA) occlusion in halothane-anesthetised rats. Treatment with CI-977 (0.3 mg/kg, s.c.) 30 min before and 30 min after occlusion of the MCA reduced the volume of infarction in the cerebral hemisphere (reduced by 27% when compared to vehicle;P<0.05) and cerebral cortex (reduced by 32%;P<0.05), despite a marked and sustained hypotension, with only minimal effect on damage in the caudate nucleus. In the hemisphere contralateral to the occluded MCA, treatment with CI-977 (0.3 mg/kg, s.c.) 30 min prior to the induction of ischemia failed to demonstrate any significant effect on either the level of local CBF in any of the 25 regions examined or on the volume of low CBF determined by frequency distribution analysis. In the hemisphere ipsilateral to MCA occlusion, CI-977 failed to produce statistically significant alterations in either the level of local CBF in 23 of the 25 regions or on the volume of low CBF, but areas of hyperemia were observed in both the medial caudate nucleus and lateral thalamus (local CBF increased by 65% and 86%, respectively, when compared to vehicle). The results of the present study indicate that the kappa-1 opioid agonist CI-977 is neuroprotective in a rat model of focal cerebral ischemia where key physiological variables have been assessed throughout the entire post-ischemic period, and fail to demonstrate that the neuroprotective effects of CI-977 in this model are due to improved blood flow to ischemic tissue.     

Biphasic expression of TGF-β1 mRNA in the rat brain following permanent occlusion of the middle cerebral artery

Two patterns of transforming growth factor-β1 (TGF-β1) expression were identified in brains of normotensive rats following permanent occlusion of the middle cerebral artery (MCAO). First, a relative increase of TGF-β1 mRNA by 37% was found at 12 h after MCAO in the ipsilateral cingulate cortex as compared to the homotopic contralateral region. The cingulate cortex is located distant from the ischemic territory. Treatment with the glutamate receptor antagonists MK-801 and NBQX did not reduce this expression (34% and 26% increase, respectively). Therefore, peri-infarct depolarization waves were probably not responsible for induction. Secondly, an increase of TGF-β1 mRNA by 116% was found at 7 days after MCAO within infarcted tissue. This expression was not reduced by the glutamate receptor antagonists MK-801 (increase 140%) and NBQX (increase 137%), either. TGF-β1 mRNA expression in the cingulate cortex at 12 h after MCAO is possibly mediated by neurons and astroglia and may support cell survival. Expression in the infarcted tissue at 7 days after MCAO is most likely related to the invasion of monocytes and may be involved in the downregulation of inflammatory events, in neoangiogenesis, and in formation of a glial scar around the infarct.     

Diffusion, perfusion, and T2 magnetic resonance imaging of anti-intercellular adhesion molecule 1 antibody treatment of transient middle cerebral artery occlusion in rat

The effect of anti-intercellular adhesion molecule-1 (anti-ICAM-1) antibody treatment of transient (2 h) middle cerebral artery (MCA) occlusion in the rat was measured using diffusion (DWI)-, T₂ (T2I)- and perfusion (PWI)-weighted magnetic resonance imaging. Rats were treated upon reperfusion with an anti-ICAM-1 monoclonal antibody (n=11) or a control antibody (n=7). DWI, T2I and PWI were performed before, during, and after induction of focal cerebral ischemia from 1 h to 7 days. In both groups, the apparent diffusion coefficient of water (ADC_w) and cerebral blood flow (CBF) values in the ischemic region significantly declined from the preischemic ADC_w values (p<0.05). The post ischemic increase in T₂ of the control group was significantly higher at 48 h than in the anti-ICAM-1 treated group (p<0.05). CBF was not significantly different between the two groups. The temporal profiles of MRI cluster analysis, which combines ADC_w and T₂ maps into a single image, was significantly different between groups. These data suggest that the neuroprotective effect of anti-ICAM-1 antibody treatment is reflected in reductions of T₂ and lesion growth during reperfusion and may not be associated with increased cerebral perfusion.