大鼠脑缺血再灌注区ICAM—1的表达与粘附性变化的实验研究

目的:观察大鼠脑缺血再灌注后缺血区ＩＣＡＭ－１ｍＲＮＡ和蛋白的表达及白细胞和血管内皮细胞间粘附性的变化。方法:４０只Ｗｉｓｔａｒ大鼠分为正常组、假手术组和缺血２ｈ再灌注２、４、１２、２４、４８、９６ｈ组,原位杂交和兔疫组化法检测ＩＣＡＭ、１ ｍＲＮＡ和蛋白表达,超高速摄录像系统观察缺血区微血管内白细胞与内皮细胞间的粘附性变化。结果:缺血再灌注后局部脑组织ＩＣＡＭ－１ｍＲＮＡ和蛋白的表达以及微动脉内白细胞与内皮细胞间粘附性均明显增高。结论:脑缺血再灌注后ＩＣＡＭ－１表达增高,介导了白细胞与血管内皮细胞间的粘附增强,参与了缺血再灌注损伤。     

大鼠局灶性脑缺血再灌注后皮层ICAM-1表达增加

目的：研究大鼠局灶性脑缺血再灌注不同时相皮层 ＩＣＡＭ－１变化规律。方法：改良 Ｋｏｉｚｕｍｉ法建立 ＬＭＣＡＯ局灶性脑缺血再灌注模型;ＲＴ－ＰＣＲ和 Ｄｏｔ ｂｌｏｔｔｉｎｇ法分别检测 ＩＣＡＭ－１的转录和翻译水平变化。结果：缺血皮层 ＩＣＡＭ－１ｍＲＮＡ和 Ｉ－ＣＡＭ－１分别于缺血 ２ｈ和再灌注 ２ｈ显著升高,再灌注 １０和 ４６ｈ达高峰,持续 １周仍维持在较高水平。结论：ＩＣＡＭ－１在脑缺血再灌注时表达明显上调,介导白细胞和脑血管内皮细胞的粘附。ＩＣＡＭ－１ 将成为缺血性脑卒中治疗的新突破点。     

小鼠局灶性脑缺血模型中细胞间粘附分子-1表达升高

目的　白细胞可以导致缺血细胞损伤,内皮细胞上表达的细胞间粘附分子－１（ＩＣＡＭ－１）有利于白细胞迁移至组织。本研究目的是对小鼠大脑中动脉栓塞（ＭＣＡＯ）后脑内ＩＣＡＭ－１ 蛋白在组织中表达和含量进行检测。方法　通过对成年雄性ＣＤ－１ 小鼠使用血管腔内尼龙线栓塞术,造成０、３、６、１２、２４、４８ 和７２ ｈ 的持续性大脑中动脉栓塞。缺血程度由激光多普勒流量仪确定,缺血脑组织ＩＣＡＭ－１ 的阳性表达由免疫组化技术检测,并用免疫沉淀和Ｗｅｓｔｅｒｎ 印迹来定量。结果　在大脑中动脉栓塞后,小鼠缺血脑半球的表面脑血流量减少到基准值的９％ ～１５％ 。各组间大脑中动脉栓塞过程中的脑血流量无显著差异。免疫组化技术显示,缺血中心区和末影区都见ＩＣＡＭ－１ 阳性的微血管内皮细胞,从缺血中心到缺血边缘区微血管内皮细胞表达ＩＣＡＭ－１ 出现增高的趋势。免疫沉淀和Ｗｅｓｔｅｒｎ 印迹分析结果表明,缺血区ＩＣＡＭ－１的表达在大脑中动脉栓塞后３ ｈ 增高,６～１２ ｈ 达到高峰,并持续到７２ ｈ。结论　研究表明,在持续性大脑中动脉栓塞的小鼠中检测到ＩＣＡＭ－１ 表达明显升高,因为在持续局灶性大脑中动脉缺血后ＩＣＡＭ－１ 可介导白细胞和内皮细胞粘附,加速     

实验性超负荷血糖大鼠脑缺血后脑毛细血管内皮细胞ICAM-1表达的研究

目的　了解超负荷血糖条件下，脑缺血后，脑毛细血管内皮细胞细胞间粘附分子１（ＩＣＡＭ－１）表达的情况。方法　采用ＳＤ大鼠尾静脉注射链脲霉素，建立超负荷血糖模型。用免疫组化方法动态观察大鼠超负荷血糖１ 月条件下以尼龙线栓堵大鼠大脑中动脉造成持续性局灶性脑缺血后不同时间，脑毛细血管内皮细胞ＩＣＡＭ－１ 的表达。结果　超负荷血糖１月脑缺血０．５ 小时ＩＣＡＭ－１ 的表达明显升高；１小时达高峰，表达范围弥漫整个缺血半球；缺血３～１２ 小时， ＩＣＡＭ－１表达仍很明显，但主要集中在颞、顶叶缺血区；缺血２４ 小时表达不明显；假手术组大鼠脑组织毛细血管内皮细胞ＩＣＡＭ－１只有较少的表达；正常血糖对照组及阴性对照者脑毛细血管内皮细胞均未见ＩＣＡＭ－１ 表达。结论　与正常血糖ＳＤ大鼠脑缺血相比，超负荷血糖大鼠脑缺血后， ＩＣＡＭ－１ 在脑毛细血管内皮细胞上表达出现的早而明显，提示对加重脑缺血后的病理损伤起到了重要作用。     

脑缺血再灌注期内皮细胞间粘附分子-1转录水平的表达

脑缺血再灌注期内皮细胞间粘附分子－１转录水平的表达余勇崔尧元刘银坤△张晓彪细胞间粘附分子－１（Ｉｎｔｅｒｃｅｌｕｌａｒａｄｈｅｓｉｏｎｍｏｌｅｃｕｌｅ－１）ＩＣＡＭ－１，属粘附分子中免疫球蛋白超家族，主要参与异种细胞粘附。最近的研究表明，细胞间...     

实验性超负荷血糖大鼠脑缺血后脑毛细血管内皮细胞ICAM—1表 …

目的 了解超负荷血糖条件下,脑缺血后,脑毛细血管内皮细胞间粘附分子１（ＩＣＡＭ－１）表达的情况。方法 采用ＳＤ大鼠尾静脉注射链脲霉素,建立超负荷血糖模型。用免疫组化方法动态观察大鼠超负荷血糖１月条件下以尼龙线栓堵大鼠中动脉造成持续性局灶性脑缺血后不同时间,脑毛细血管内皮细胞ＩＣＡＭ－１的表达。结果 超负荷血糖１月脑缺血０．５小时ＩＣＡＭ－１的表达明显升高;１小时达高峰,表达范围弥漫整个缺血半球;缺     

TNF-α对血管内皮细胞VCAM-1诱导作用的研究

目的：探讨肿瘤坏死因子－α（ＴＮＦ－α）对血管内皮细胞ＶＣＡＭ－１表达的诱导作用。方法：通过血管内皮细胞培养,采用免疫组织化学方法分别观察不同浓度ＴＮＦ－α（０．２５０Ｕ．ｍＬ＾－１）２４小时内以及相同浓度（１００Ｕｍｌ＾－１）ＴＮＦ－μ０－α０－７２ｈ对内皮细胞ＶＣＡＭ－１表达的影响。结果：与对照组比较,ＴＮＦ－α对内皮细胞ＶＣＡＭ－１的诱导作用具有明显浓度与时间依赖性。结论：ＴＮＦ－α可诱导血     

脑缺血抗细胞间粘附分子—1抗体作用的实验研究

目的探讨抗细胞间粘附分子－１（ＩＣＡＭ－１）抗体保护神经元缺血性损伤的作用机制。方法分离培养鼠脑毛细血管内皮细胞（ＣＣＥＣ）和多形核白细胞（ＰＭＮ），利用微管吸吮技术，观察ＰＭＮ与ＣＣＥＣ间粘附力学特性的变化。结果脑缺血－再灌注后各时间点，ＰＭＮ与ＣＣＥＣ的粘附力和粘附应力均明显高于正常对照组和伪手术组（Ｐ＜０．０１）；加抗ＩＣＡＭ－１抗体后，细胞粘附力和粘附应力均明显下降（Ｐ＜０．０５或Ｐ＜０．０１）。结论脑缺血－再灌注损伤后抗ＩＣＡＭ－１抗体使ＰＭＮ与ＣＣＥＣ粘附力减小，粘附应力下降；抗粘附分子抗体将可能成为治疗缺血性脑血管疾病的一条新的有效途径     

氧化修饰低密度脂蛋白刺激血管内皮细胞表达VCAM-1的实验研究

目的：探讨氧化修饰低密度脂蛋白（ＯＸ－ＬＤＬ）对血管内皮细胞表达血管细胞粘附分子－１（ＶＣＡＭ—１）的影响,以阐明其在动脉粥样硬化发生中的作用。方法：在血管内皮细胞的培养基中分别加入２５μｇ／ｍｌ的低密度脂蛋白（ＬＤＬ）和ＯＸ－ＬＤＬ,３7℃下温育 ２４小时,应用定量免疫细胞化学分析技术检测内皮细胞 ＶＣＡＭ－１蛋白的表达。结果：与对照组和ＬＤＬ组比较,ＯＸ－ＬＤＬ组内皮细胞ＶＣＡＭ－１蛋白的表达显著增加。结抡：ＯＸ－ＬＤＬ能够明显刺激内皮细胞ＶＣＡＭ－１的表达。     

脑水肿时血脑屏障内皮细胞ICAM—1的表达及其对T淋巴细胞粘附的 …

本研究采用液氮冷冻Ｗｉｓｔａｒ大鼠一侧大脑制成血管源性脑水肿模型，将大鼠全脑沿冷冻中心制成冠状面冰冻切片，运用免疫组化染以观察脑水肿及对照组白质血脑屏障内皮细胞ＩＣＡＭ－１蛋白表达量的变化。对此进行图像分析，并将脑组织冰冻切片与大量Ｔ淋巴细胞悬液共同孵育后，常规ＨＥ染色、显微镜下观察，求出Ｔ淋巴细胞与血管壁的特异生附率，发现大鼠内皮细胞在正常情况下表达少量的ＩＣＡＭ－１蛋白分子，冷冻后３小时有明显     

脑梗死患者中性粒细胞与血管内皮细胞黏附性的研究

目的　分析脑梗死后外周血中性粒细胞 (PMN)与血管内皮细胞 (EC)黏附性的变化规律 ,探讨抗细胞间黏附分子 1单克隆抗体 (ICAM 1mAb)对其影响。方法　用细胞计数法检测 30例脑梗死患者梗死后 1周以内、2 1天时PMN与经 (或不经 )ICAM 1mAb处理的人类脐静脉内皮细胞细胞株ECV 30 4的黏附率。结果(1)脑梗死患者PMN与ECV 30 4的黏附率在 1周以内明显增高 ,到第 2 1天时显著下降 ;(2 )ICAM 1mAb可以明显降低 1周以内脑梗死患者PMN与ECV 30 4的黏附 (P <0 .0 1) ,而 2 1天时脑梗死患者和健康对照组PMN与ECV 30 4黏附则影响较小 (P <0 .0 5 )。结论　 (1)急性期脑梗死患者PMN与EC黏附增强 ,到恢复期时基本正常 ;(2 )ICAM 1参与介导脑梗死急性期PMN与EC的黏附 ,ICAM 1mAb可部分阻断PMN与EC黏附     

Expression of leucocyte adhesion molecules at the human blood-brain barrier (BBB).

The expression of leucocyte adhesion molecules was studied on cerebral endothelia by immunocytochemistry. In peritumoral "normal" brain tissue we found low endothelial expression of ICAM1, LFA3, CD44, and CD9, whereas VLA1 was present on vessels in high incidence and density. LFA1, CD2, and CR3 were found on intraluminal and parenchymal leucocytes, but were absent on brain vessels. In brain tumors and inflammatory brain lesions, we observed an up-regulation of endothelial ICAM1 and LFA3 expression, whereas other adhesion molecules on endothelial cells remained unchanged. Within the brain parenchyma, ICAM1 and LFA3 were found on astrocytes and tumor cells; on the contrary, LFA1 was expressed on microglial cells similar to CR3. CD44 and CD9 showed a diffuse neuropil expression in normal and tumoral tissue, whereas VLA1 was not expressed on any parenchymal cells. Our data show that multiple different adhesion molecules are present on blood-brain barrier endothelium (BBB) under normal conditions and some adhesion molecules are up-regulated in brain tumors and under inflammatory conditions. The presence of adhesion molecules in the vessel walls as well as on parenchymal cells like astrocytes and microglia may guide inflammatory cells into and through the brain in the course of immune surveillance and inflammation.     

缺氧/复氧后星形胶质细胞AQP5表达的变化及亚低温的干预效应

目的观察缺氧/复氧条件下大脑星形胶质细胞水通道蛋白5(AQP5)的表达变化以及亚低温对其表达的影响。方法利用新生24 h内的SD大鼠,进行原代、传代培养,将星形胶质细胞分为对照组、常温组及亚低温组。用台盼蓝染色法测定37℃及32℃时,缺氧/复氧不同时间点星形胶质细胞的存活率,作为细胞受损指标,用倒置相差显微镜对细胞进行形态学观察,应用细胞免疫化学技术检测星形胶质细胞缺氧/复氧各个时间点AQP5的表达变化及亚低温的干预效果。结果 (1)缺氧4、8 h细胞形态变化不明显,随着复氧时间的延长,可见活化逐渐明显,而亚低温干预的细胞形态及细胞存活力变化均较相应的常温组明显减轻;(2)缺氧及复氧早期AQP5的表达水平降低,复氧后6 h随着时间延长AQP5表达明显增多,在复氧≤8 h常温组及亚低温组的表达水平均低于对照组(P<0.05或0.01),而复氧后10、12 h AQP5蛋白表达水平均明显高于对照组(P<0.05或0.01);(3)在复氧后各时间点亚低温组AQP5的表达水平均明显低于常温组(P<0.05或0.01)。结论亚低温可以减轻缺氧/复氧后星形胶质细胞的损伤,通过降低AQP5的表达水平,可能是亚低温减轻缺血性脑水肿的作用机制之一。     

大鼠脑缺血再灌注模型ICAM-1表达与白细胞浸润关系及亚低温干预治疗的研究

目的　研究大鼠局灶性脑缺血再灌注后不同时程脑组织中的细胞间粘附分子 1 (ICAM 1 )表达规律 ,及其与白细胞浸润的关系 ,并探讨亚低温的治疗作用。方法　采用大鼠大脑中动脉 (MCA)线拴闭塞 /再通法建立大鼠局灶性脑缺血 再灌注模型 ,常温组分别于脑缺血 3小时再灌注 2小时、8小时、2 4小时、48小时、72小时后断头取脑 ;假手术组及亚低温组于脑缺血 3小时再灌注 2 4小时断头取脑 ,行ICAM 1免疫组化及组织HE染色 ,测定ICAM 1表达阳性微血管数及白细胞计数。结果　⑴脑缺血再灌注后 2小时 ,脑缺血的坏死周边区的微血管内皮细胞表达ICAM 1出现增高趋势 ,并于 2 4小时达到高峰 ,各组之间及各组与假手术组间均有显著差异 (均P <0 0 5) ;⑵脑缺血再灌注 8小时出现白细胞浸润 ,且浸润高峰也在 2 4小时 (P <0 0 1 ) ;⑶ICAM 1的表达与白细胞浸润呈正相关 (r =0 .82 7,P <0 0 1 ) ;⑷缺血早期进行亚低温治疗能明显减轻缺血再灌注后ICAM 1的表达及减少白细胞浸润 (P <0 0 1 )。结论　脑缺血再灌注后ICAM 1可介导白细胞和内皮细胞的粘附 ,加速白细胞的浸润 ,提示ICAM 1是造成脑缺血损伤的重要因素之一 ;亚低温的干预治疗能明显减轻缺血再灌注后脑组织病理形态学的损害程度。     

The protective effects of preconditioning on cerebral endothelial cells in vitro.

Ischemic preconditioning (PC) can markedly reduce ensuing ischemic damage. Although most attention has focused on the neuronal effects of PC, the authors have recently shown that ischemic PC reduces ischemia-induced cerebrovascular damage. In vivo, it is difficult to ascertain whether this is a direct cerebrovascular effect of PC. This study, therefore, examined whether cerebral endothelial cells can be preconditioned in vitro in the absence of other cell types. Experiments were performed on an immortalized mouse brain endothelial cell line or primary cultures of mouse brain microvessel endothelial cells. Cells were exposed to oxygen glucose deprivation (OGD) of either short duration, as a PC stimulus, or a long duration (5 hours) with or without reoxygenation to induce endothelial damage. Endothelial injury was assessed by measuring lactate dehydrogenase release and the expression of intercellular adhesion molecule-1 at the protein and mRNA levels. Experiments indicated that 1 hour of OGD was the optimal PC stimuli and that a 1 or 3 day interval was the optimal time interval between the PC stimulus and the injurious event. Preconditioned cells had less lactate dehydrogenase release during OGD (+/- reoxygenation) and reduced intercellular adhesion molecule-1 expression after OGD with reoxygenation. This study shows that cerebral endothelial cells can be directly preconditioned. The importance of this phenomenon in the overall effects of PC on the brain remains to be elucidated. Understanding the protective mechanisms elicited by PC may give insight into how to prevent ischemia-induced vascular damage (e.g., hemorrhagic transformation).     

Syndecan-4-dependent signaling in the inhibition of endotoxin-induced endothelial adherence of neutrophils by antithrombin

Circulating endotoxin is elevated in sepsis and plays a role in endothelial dysfunction whereas antithrombin is decreased by virtue of its consumption during complex formation with clotting factors and by proteolytic degradation by granulocyte elastase. Dysfunction of endothelium results in enhanced leukocyte rolling and diapedesis into tissues leading to edema formation and injury. Antithrombin exerts beneficial effects on endothelial function in sepsis. A direct anti-inflammatory action of anti-thrombin in inflammatory cells is exerted via heparan sulfate proteoglycans. In this study, we investigated whether antithrombin affects endotoxin-induced adhesion of neutrophils to human endothelial cells in vitro and whether glycosaminoglycans are involved in its signaling. Adhesion of human neutrophils to monolayers of umbilical vein endothelial cells was tested under static conditions. Endothelial cells were pretreated with endotoxin, interleukin-1, heparinase-I, chondroitinase-ABC or anti-syndecan-4-antibody. Endotoxin and interleukin-1 increased neutrophil adherence to human umbilical vein endothelial cells which was inhibited by antithrombin. Concomitant incubation with pentasaccharide abolished this effect of antithrombin. Treatment of endothelial cells with heparinase or chondroitinase led to higher adhesion and prevented effects of antithrombin. With antibodies to syndecan-4, enhanced adhesion of neutrophils was observed. As studied by Western blotting, endotoxin-induced signaling was diminished by antithrombin and the effect was reversible by chondroitinase or heparinase. From our results, we can conclude that endotoxin-induced adhesion of leukocytes to endothelium can be reversed by ligation of syndecan-4 with antithrombin's heparin-binding site and interferences with stress response signaling events in endothelium.