EAE大鼠胸腺CD4~+ CD25~+ Foxp3~+ Treg细胞的动态变化及α-硫辛酸的干预作用

目的探讨实验性变态反应性脑脊髓炎(EAE)大鼠不同病程中胸腺CD4+CD25+Foxp3+Treg细胞变化情况及α-硫辛酸对EAE大鼠胸腺的干预作用。方法取不同时期对照组、自然病程EAE组及α-硫辛酸EAE组大鼠的胸腺组织做流式细胞学,动态检测CD4+CD25+Foxp3+Treg细胞的变化情况。结果 EAE组大鼠急性期、复发期CD4+CD25+Foxp3+Treg细胞较同时期对照组明显减少(P<0.05),缓解期有所上升;α-硫辛酸组与同期EAE组相比CD4+CD25+Foxp3+Treg细胞无明显变化;半年期三组大鼠胸腺CD4+CD25+Foxp3+Treg细胞都明显下降,各组间无统计学差异。结论 CD4+CD25+Foxp3+Treg细胞参与了EAE的发病,与病程的发展密切相关;α-硫辛酸对EAE大鼠的干预作用并非通过CD4+CD25+Foxp3+Treg细胞发挥其治疗作用;随着年龄的增长,胸腺不再是机体的主要免疫器官。     

供体凋亡淋巴细胞预输注对猪肝移植受体CD4+T、CD8+T、CD4+CD25+调节性T细胞的影响

背景：凋亡细胞能够主动调节机体的免疫功能,并能通过调节机体细胞免疫和体液免疫的途径诱导免疫耐受,但这些结果只在大鼠肝脏移植模型中证实。 目的：探讨通过60Co γ射线体外处理后的供体淋巴细胞预输注诱导猪肝移植特异性免疫耐受的作用中,对淋巴细胞亚群的影响。 方法：建立非转流小型猪原位肝移植模型。将受体猪随机摸球法均分为2组：空白对照组,受体猪无特殊处理,行肝移植;淋巴细胞组：受体猪在肝移植前7 d经耳静脉注射60Co γ射线处理过的5×108个供体淋巴细胞。观察两组受体猪移植后的存活时间,移植后T淋巴细胞亚型CD4+T、CD8+T、CD4+CD25+Tr变化及病理。 结果与结论：移植后3 d,两组病理活检均呈急性中、重度排斥反应;移植后6 d,两组均呈急性重度排斥反应。移植后1,3,6 d CD4+T、CD8+T、CD4+CD25+Tr升降趋势,两组间差异无显著意义(P > 0.05)。提示,60Co γ射线体外处理过的淋巴细胞预输注未能够诱导猪同种异体肝移植特异性免疫耐受,未能引起T淋巴细胞亚群变化有关。     

甘露醇促进人脐血CD34+细胞通过血脑屏障静脉迁移至高血压脑梗死大鼠脑组织

背景：单纯脐血细胞经静脉移植治疗脑梗死疗效有限，移植细胞经血脑屏障迁入脑内数量不足为重要原因之一。 目的：观察血脑屏障开放剂甘露醇对人脐血CD34+细胞经静脉移植治疗高血压大鼠脑梗死疗效的影响。 方法：分离人脐血CD34+细胞，脂质体方法转染pEGFPF质粒，制备pEGFP-CD34+细胞；45只雄性SD大鼠经线栓法建立大脑中动脉栓塞模型，造模后24 h随机分为3组：实验组注射1×106 GFP-CD34+细胞，继之注射20%甘露醇2 g/kg；阳性对照组注射1×106 GFP-CD34+细胞；空白对照组注射等量生理盐水。 结果与结论：①荧光显微镜下实验组每张切片脑组织GFP标记阳性的绿色荧光细胞计数平均值显著多于阳性对照组。②移植后第7天治疗组与其他各组神经功能损害评分差异无显著性意义；移植后28 d，各组神经功能均有不同程度恢复，实验组神经功能恢复明显优于阳性对照组和空白对照组(P < 0.05)。③实验组与其他两组相比，大鼠脑梗死体积均显著减少。④实验组脑组织匀浆胶质细胞源性神经营养因子水平较阳性对照组、空白对照组明显增高。提示血脑屏障开放剂甘露醇促进静脉移植CD34+细胞通过血脑屏障迁入至脑组织，并增强静脉移植CD34+细胞治疗脑梗死的疗效。     

外周血CD4+CD25highTreg细胞的比例变化在肾移植受者术后免疫监测中的临床应用研究

目的 研究外周血CD4+CD25highTreg细胞(regulatory T cell,Treg)比例对肾移植受者免疫力的影响,为CD4+CD25highTreg细胞的比例变化作为评估移植受者免疫状态及作为预测排斥反应和感染的特异性指标提供实验依据。方法 肾移植受者52例按肾移植术后恢复情况分为免疫力正常组26例,发生排斥反应组17例,发生感染组9例,用流式细胞仪检测外周血CD4+CD25highTreg细胞的比例,所得结果进行相关分析。结果 发生急性排斥反应组CD4+CD25highTreg细胞比例较免疫力正常组显著降低（p〈0.05）,发生感染组外周血CD4+CD25highTreg细胞的比例较正常组显著升高（p〈0.01）,均有统计学意义。FK-506和CsA分别对CD4+CD25highTreg细胞比例的影响没有显著性差异。结论 肾移植术后受者外周血CD4+CD25highTreg细胞比例与受者免疫状态密切相关。CD4+CD25highTreg细胞比例的变化可以反应机体的免疫状态的变化,其升高或降低可以作为预测肾移植受者术后发生感染或排斥反应的指标之一。     

重症肌无力患者Foxp3~+CD4~+CD25~+调节性T细胞与AChRAb、Titin-Ab的相关研究

目的探讨重症肌无力(myasthenia gravis,MG)患者Foxp3~+CD4~+CD25~+调节性T细胞(Foxp3~+CD4~+CD25~+Treg)与乙酰胆碱受体抗体(AChRAb)及连接素抗体(Titin-Ab)之间的关系,进一步揭示MG的发病机制。方法采用酶联免疫吸附试验(ELISA)检测22例MG患者以及20名健康对照者血清AChRAb和Titin-Ab水平;采用流式细胞术(FCM)检测两组外周血中CD4~+CD25~+Treg的比例及其表达Foxp3的比例。结果 MG患者外周血CD4~+CD25~+Treg比例[(2.9±0.52)%]与健康对照组[(3.12±0.51)%]比较无统计学差异(P0.05);CD4~+CD25~+Treg细胞Foxp3表达比例为(37.24±9.57)%,低于健康对照组[(58.60±4.91)%](P0.01)。MG组CD4~+CD25~+Treg表达Foxp3比例与AChRAb、Titin-Ab水平[分别为(0.232±0.060)和(0.170±0.035)pg/mL]均呈负相关(r=-0.449,P0.05;r=-0.691,P0.01)。结论 Foxp3~+CD4~+CD25~+Treg细胞数目减少导致机体免疫功能缺陷是MG发病的重要环节。     

CD4~+、CD25~+、CD127 low调节T细胞及CD16~+、CD56NK细胞在脑梗死急性期患者外周血中的表达及其关系

目的探讨脑梗死(CI)患者外周血中CD4+、CD25+、CD127 low调节T细胞及CD16+、CD56NK细胞的百分比变化及两者在CI患者免疫反应中的相互作用机制。方法采用流式细胞术检测50例急性CI患者(发病2d)外周血中CD4+、CD25+、CD127 low调节T细胞及CD16+、CD56NK细胞的表达水平,并与健康对照组进行比较。结果急性CI患者(发病2d)外周血中的CD4+、CD25+、CD127 low调节T细胞的表达水平低于健康对照组,而CD16+、CD56NK细胞的数量则明显高于健康对照组(p<0.05)。结论急性CI患者发病2d,CD16+、CD56NK细胞表达水平上升,而CD4+、CD25+、CD127 low调节性T细胞表达明显低于健康对照组,说明CD4+、CD25+、CD127 low调节性T细胞和CD16+、CD56NK细胞是促进CI发生的原因之一。     

肾移植患者外周血中的CD4+ CD25+ CD127low/-调节性T细胞

背景：越来越多的实验在分析免疫耐受标志,以期能够更好地辅助患者进行移植后免疫抑制治疗。 目的：分析肾移植后患者外周血中CD4+ CD25+ CD127low/-调节性T细胞在肾移植免疫耐受中的作用。 方法：采集62例肾移植后患者(急性排斥反应组22例,移植稳定组40例)及20例健康对照者的外周抗凝血,经免疫染色,应用流式细胞仪分析CD4+ CD25+ CD127low/-调节性T细胞所占CD4+ T细胞百分含量,同时采用ELISA方法检测患者血清中白细胞介素2和白细胞介素10的质量浓度。 结果与结论：移植稳定组中CD4+ CD25+ CD127low/-调节性T细胞所占CD4+ T细胞百分含量显著高于健康对照组和急性反应排斥组(P < 0.01);CD4+ CD25+ CD127low/-调节性T细胞百分含量与白细胞介素2呈显著负相关(P < 0.05),与白细胞介素10呈显著正相关(P < 0.01)。提示CD4+ CD25+ CD127low/-调节性T细胞在肾移植后免疫耐受的机制中发挥了一定作用。     

影响外周血CD34+细胞纯化的相关因素

背景：造血干细胞具有良好的自我复制和更新的能力,CD34+细胞具备有造血干细胞的标志。 目的：分析影响外周血CD34+细胞纯化的因素。 方法：90例患者,经粒细胞集落刺激因子5 μg/(kg•d)动员1~3 d后,应用COBE血细胞分离机采集外周血单个核细胞液80~100 mL,经Clini MACS免疫磁珠分选技术纯化CD34+细胞。 结果与结论：90例CD34+细胞平均数为(1.73±1.15)×107,经流式细胞仪分析,CD34+细胞阳性率大于80%。COBE血细胞分离机单次收集的循环血量在980~1 100 mL时,利于CD34+细胞收集(P=0.005);动员后白细胞浓度在(16~21)×109 L-1时,利于CD34+细胞收集(P < 0.05);中间细胞和淋巴细胞总比例超11%时,利于CD34+细胞收集(P < 0.05);单个核细胞液血小板小于2 100×109 L-1时,利于CD34+细胞的收集(P < 0.05);年龄小于16岁,CD34+细胞数高(P=0.003);CD34+细胞抗体的温度、磁性标记及细胞处理时离心力的大小,均有影响。结果提示,经Clini MACS免疫磁珠细胞分选技术纯化的CD34+细胞能满足临床需要,实验稳定性好,重复性好;注重相关因素的影响,可提高纯化的CD34+细胞数量。     

睾丸内胰岛移植对CD4+ CD25+调节性T细胞分布的影响

背景：CD4+ CD25+调节性T细胞是维持机体免疫耐受的重要调控者，参与了多种移植免疫耐受的诱导。 目的：拟观察小鼠睾丸内胰岛移植后CD4+ CD25+调节性T细胞分布的特点。 设计、时间及地点：观察对照动物实验，2007-04/2008-01在江西省实验动物中心完成。 材料：成年Balb/c小鼠。 方法：分离小鼠胰岛细胞，采用胰管内注射胶原酶水浴消化及Ficoll 400不连续密度梯度离心法纯化，以双硫腙染色，计算胰岛细胞纯度，以体外葡萄糖刺激胰岛素分泌试验判定胰岛细胞功能。将胰岛移植至小鼠睾丸或肾包膜下，每只移植300~400个胰岛。在胰岛移植24 h后麻醉处死小鼠，取脾脏、睾丸及淋巴结，制成细胞悬液，免疫磁珠法分离CD4+CD25+ T细胞，通过流式细胞仪分析计数。 主要观察指标：胰岛细胞的纯度及功能，CD4+ CD25+调节性T细胞的分布。 结果：纯化后每只胰腺获得(478±53)个胰岛细胞，纯度为(81.5±12.3)%，纯化后细胞形态完好，活度大于90%。睾丸内胰岛移植时，睾丸、淋巴结及脾脏中CD4+CD25+调节性T细胞均显著增多（P < 0.05~0.01）。 结论：睾丸内胰岛移植能明显上调睾丸、淋巴结及脾脏中CD4+ CD25+调节性T细胞数量。     

人脐血CD34+细胞移植对局灶性脑缺血大鼠神经功能恢复的影响*☆

目的：CD34+造血干细胞具有自我更新、多向分化及重建长期造血和免疫的生物学功能，针对心肌缺血性损伤、肢体血管闭塞引起的组织缺血等治疗有显著的疗效。由于中枢神经系统缺血性损伤临床治疗康复效果不佳，观察人脐带血CD34+细胞移植对大鼠大脑中动脉栓塞后神经功能恢复的影响及CD34+细胞的存活、迁移以及向神经细胞分化的情况。 方法：实验于2002-05起在天津市中国医学科学院中国协和医科大学血液学研究所进行。①实验材料：雄性SD大鼠由解放军军事医学科学院第四研究所提供，体质量250~350 g，实验过程中对动物处置符合动物伦理学标准。人脐带血由天津脐血干细胞库提供，产妇及家属对实验知情同意，并符合医学伦理学标准。②实验方法：将大鼠随机分为3组：CD34+细胞移植组：用线栓法建立大鼠左侧大脑中动脉栓塞模型后24 h移植CD34+细胞；生理盐水组：左侧大脑中动脉栓塞后24 h后注射等量的生理盐水；假手术组：仅行左侧大脑中动脉栓塞。③实验评估：采用改良神经功能损害评分观察大鼠神经功能恢复情况，应用免疫组织化学和免疫荧光双标记技术检测BrdU标记的CD34+细胞存活、迁移及其GFAP蛋白和NeuN蛋白的表达。 结果：①CD34+细胞移植组与其它各组在移植完成24 h 改良神经功能损害评分差异无显著性（P > 0.05）; 移植后1周到第4周，各组动物均有神经功能不同程度的恢复，CD34+细胞移植组神经功能恢复明显优于另两组（P < 0.05）。②CD34+细胞移植组与另两组比较，大鼠脑梗死体积无明显变化。③移植的CD34+细胞可在大鼠脑组织中存活，部分CD34+细胞同时表达GFAP蛋白或NeuN蛋白，并向缺血区域迁移。 结论：CD34+细胞可在大鼠脑缺血区域中存活、迁移并向星形胶质细胞或神经元分化，同时促进神经功能恢复。     

Functional assay for human CD4+CD25+ Treg cells reveals an age-dependent loss of suppressive activity

CD4+CD25+ regulatory T cells (Treg cells) prevent T cell-mediated autoimmune diseases in rodents. To develop a functional Treg assay for human blood cells, we used FACS- or bead-sorted CD4+CD25+ T cells from healthy donors to inhibit anti-CD3/CD28 activation of CD4+CD25- indicator T cells. The data clearly demonstrated classical Treg suppression of CD4+CD25- indicator cells by both CD4+CD25(+high) and CD4+CD25(+low) T cells obtained by FACS or magnetic bead sorting. Suppressive activity was found in either CD45RO- (naive) or CD45RO+ (memory) subpopulations, was independent of the TCR signal strength, required cell-cell contact, and was reversible by interleukin-2 (IL-2). Of general interest is that a wider sampling of 27 healthy donors revealed an age- but not gender-dependent loss of suppressive activity in the CD4+CD25+ population. The presence or absence of suppressive activity in CD4+CD25+ T cells from a given donor could be demonstrated consistently over time, and lack of suppression was not due to method of sorting, strength of signal, or sensitivity of indicator cells. Phenotypic markers did not differ on CD4+CD25+ T cells tested ex vivo from suppressive vs. nonsuppressive donors, although, upon activation in vitro, suppressive CD4+CD25+ T cells had significantly higher expression of both CTLA-4 and GITR than CD4+CD25- T cells from the same donors. Moreover, antibody neutralization of CTLA-4, GITR, IL-10, or IL-17 completely reversed Treg-induced suppression. Our results are highly consistent with those reported for murine Treg cells and are the first to demonstrate that suppressive activity of human CD4+CD25+ T cells declines with age.     

Secondary progressive in contrast to relapsing-remitting multiple sclerosis patients show a normal CD4+CD25+ regulatory T-cell function and FOXP3 expression

Accumulating evidence indicates an immunosuppressive role for CD4(+)CD25(+) regulatory T cells (Tregs) in autoimmune diseases. Although an impaired Treg function in patients with relapsing-remitting multiple sclerosis (RR-MS) has been reported recently, no information is available so far about Treg function in the progressive stage of the disease. In the present study, the phenotypic and functional characteristics of CD4(+)CD25(+) T cells isolated from the peripheral blood of patients with RR-MS and secondary progressive multiple sclerosis (SP-MS) were investigated. No significant quantitative or phenotypic abnormalities in CD4(+)CD25(+) T cells from RR- and SP-MS patients were detected. However, whereas a reduced suppressor function of CD4(+)CD25(+) T cells toward proliferation and interferon-gamma production of CD4(+)CD25(-) responder T cells was found in RR-MS patients, SP-MS patients showed a normal Treg function. The suppressive capacity of MS-derived CD4(+)CD25(+) T cells was correlated with disease duration but not with age, indicating that Treg function is more affected in the early phase of the disease process. Consistently with the suppressive capacity, CD4(+)CD25(+) T cells from SP-MS patients showed normal levels of FOXP3 mRNA in contrast to RR-MS patients that had a reduced FOXP3 expression. These data are the first to demonstrate differences in function and FOXP3 expression of CD4(+)CD25(+) T cells from patients with RR- and SP-MS.     

抑郁症自杀未遂患者若干生物学改变

目的:探讨抑郁症自杀未遂患者外周血中CD4+CD25+调节性T(Tr)细胞、白细胞介素2(IL-2)及IL-6水平与自杀行为间的关系。方法:患者组为44例抑郁症自杀未遂患者,对照组为30名健康正常者。患者组用选择性5-羟色胺再摄取抑制剂或文拉法辛治疗。治疗前后检测CD4+CD25+Tr、IL-2及IL-6。采用自杀未遂调查表评定两组严重程度。结果:患者组治疗前外周血中CD4+CD25+Tr、IL-2及IL-6均显著高于对照组(P<0.05或P<0.01)。患者组治疗后外周血中CD4+CD25+Tr、IL-2显著降低(P<0.01),IL-6变化不明显。两组比较差异无统计学意义(P>0.05)。患者病情严重程度与血中CD4+CD25+Tr、IL-2、IL-6水平均无显著相关。结论:抑郁症自杀未遂患者处于免疫紊乱状态,CD4+CD25+Tr、IL-2、IL-6与自杀行为间存在一定的关系。     

Immunotherapy of rat glioma without accumulation of CD4~+CD25~+FOXP3~+ regulatory T cells

Immunotherapy may be used for the treatment of glioblastoma multiforme;however,the induced immune response is inadequate when either T cells or dendritic cells are used alone.In this study,we established a novel vaccine procedure in rats,using dendritic cells pulsed with C6 tumor cell lysates in combination with adoptive transfer of T lymphocytes from syngenic donors.On day 21 after tumor inoculation,all the rats were sacrificed,the brains were harvested for calculation of glioma volume,cytolytic T lymphocyte responses were measured by cytotoxic assay,and the frequency of regulatory T lymphocytes(CD4+CD25+FOXP3+) in the peripheral blood was investigated by flow cytometric analysis.The survival rate of rats bearing C6 glioma was observed.Results showed that the co-immunization strategy had significant anti-tumor potential against the pre-established C6 glioma,and induced a strong cytolytic T lymphocyte response in rats.The frequency of peripheral blood CD4+CD25+FOXP3+ regulatory T lymphocytes was significantly decreased following the combination therapy,and the rats survived for a longer period.Experimental findings indicate that the combined immunotherapy of glioma cell lysate-pulsed dendritic cell vaccination following adoptive transfer of T cells can effectively inhibit the growth of gliomas in rats,boost anti-tumor immunity and produce a sustained immune response while avoiding the accumulation of CD4+CD25+FOXP3+ regulatory T lymphocytes.     

造血干细胞与神经生长因子联合移植治疗脑梗死

背景：目前采用外周血造血干细胞移植治疗脑缺血方面的研究还比较少,缺乏大量、系统的实验数据。神经生长因子可调控神经元再生所需的微环境,对神经细胞的存活、增殖起重要作用。 目的：观察造血干细胞移植后,神经生长因子对其在脑梗死大鼠脑内的存活、分化及神经功能的影响。 设计：随机对照动物实验。 材料：清洁级成年雄性SD大鼠120只,随机分为3组：单纯细胞移植组、细胞移植+神经生长因子组、模型对照组,40只/组。神经生长因子为北大之路药业有限公司产品。 方法：大鼠颈部皮下注射重组人粒细胞集落刺激因子后,密度梯度离心法分离培养造血干细胞,移植前行Brdu标记。3组大鼠根据改良Longa线栓法建立大脑中动脉闭塞模型,造模后7 d,大鼠麻醉后暴露前囟,选取注射位点：前囟后方1.2 mm,中线向右旁开3 mm,硬膜下4 mm。单纯细胞移植组缓慢注入1×106个造血干细胞,细胞移植+神经生长因子组注入1×106个造血干细胞+200 ng神经生长因子,模型对照组给予等量磷酸盐缓冲液。 主要观察指标：采用神经功能缺损评分检测神经功能的改善情况,免疫组化染色观察梗死半球Brdu/CD34、Brdu/Nestin、Brdu/NSE、Brdu/vWF双阳性细胞的分布,TCC染色观察梗死体积的变化。 结果：与移植前比较,移植后1,2周仅细胞移植+神经生长因子组神经功能缺损评分均明显下降(P < 0.05),移植后3,4周各组神经功能缺损评分均明显下降(P < 0.05或0.01),且细胞移植+神经生长因子组下降幅度尤为显著(P < 0.01)。移植后1周,细胞移植+神经生长因子组Brdu/CD34、Brdu/Nestin、Brdu/NSE、Brdu/vWF双阳性细胞数明显多于单纯细胞移植组(P < 0.01);第4周两组未见Brdu/CD34双阳性细胞,Brdu/Nestin较1周时减少,Brdu/NSE、Brdu/vWF双阳性细胞均明显增多(P < 0.05),且细胞移植+神经生长因子组明显多于单纯细胞移植组(P < 0.01);模型对照组始终未见Brdu双阳性细胞。 结论：神经生长因子对外源性移植的造血干细胞在局灶性脑梗死大鼠脑内存活、分化以及神经功能的恢复具有明显促进作用。     

Endogenous CD4+BV8S2- T cells from TG BV8S2+ donors confer complete protection against spontaneous experimental encephalomyelitis (Sp-EAE) in TCR transgenic,RAG-/- mice

To investigate regulatory mechanisms which naturally prevent autoimmune diseases, we adopted the genetically restricted immunodeficient (RAG‐1^?/?) myelin basic protein (MBP)‐specific T cell receptor (TCR) double transgenic (T/R?) mouse model of spontaneous experimental autoimmune encephalomyelitis (Sp‐EAE). Sp‐EAE can be prevented after transfer of CD4+splenocytes from naïve immunocompetent mice. RAG‐1+ double transgenic (T/R+) mice do not develop Sp‐EAE due to the presence of a very small population (about 2%) of non‐Tg TCR specificities. In this study, CD4+BV8S2+ T cells that predominate in T/R+ mice, and three additional populations, CD4+BV8S2?, CD4?CD8?BV8S2+, and CD4?CD8+BV8S2+ T cells that expanded in T/R+ mice after immunization with MBP‐Ac1‐11 peptide, were studied for their ability to prevent Sp‐EAE in T/R? mice. Only the CD4+BV8S2? T cell population conferred complete protection against Sp‐EAE, similar to unfractionated splenocytes from non‐Tg donors, whereas CD4?CD8?BV8S2+ and CD4+BV8S2+ T cells conferred partial protection. In contrast, CD4?CD8+BV8S2+ T cells had no significant protective effects. The highly protective CD4+BV8S2? subpopulation was CD25+, contained non‐clonotypic T cells, and uniquely expressed the CCR4 chemokine receptor. Protected recipient T/R? mice had marked increases in CD4+CD25+ Treg‐like cells, retention of the pathogenic T cell phenotype in the spleen, and markedly reduced inflammation in CNS tissue. Partially protective CD4+BV8S2+ and CD4? CD8?BV8S2+ subpopulations appeared to be mainly clonotypic T cells with altered functional properties. These three Sp‐EAE protective T cell subpopulations possessed distinctive properties and induced a variety of effects in T/R? recipients, thus implicating differing mechanisms of protection. © 2002 Wiley‐Liss, Inc.     

大鼠脑局灶缺血／再灌注对外周血单个核CD34^＋细胞的影响

目的本研究探讨大鼠脑局灶缺血/再灌注是否影响外周血单个核CD34+细胞的数量.方法采用大鼠大脑中动脉(MCA)缺血/再灌注线栓法模型,将大鼠随机分为3组对照组,假手术组,动物模型组.取再灌注后1、3、6、12 h和1、2、3、4、7、14 d,10个观察点,测外周血单个核CD34+表达情况.结果大鼠脑缺血/再灌注模型中外周血单个核CD34+细胞在再灌注后1 h～2 d无明显变化,在脑缺血/再灌注后3～7 d明显减少,14 d后恢复.结论大鼠脑缺血/再灌注模型再灌注后1 h～2 d再灌注后外周血单个核CD34+细胞没有变化,在脑缺血/再灌注后3～7 d明显减少.