神经干细胞超顺磁性氧化铁纳米粒子标记和体内MRI示踪

神经干细胞（neural stem cell，NSC）是当今医学的前沿课题，困扰其临床应用的一个难题是如何对移植进入体内的神经干细胞进行监测，观察其存活和迁徙的情况。在中枢神经系统的不同病理、生理条件下，移植的神经干细胞有着不同的迁徙和分化能力，对干细胞这一特性的研究目前多为在移植后的一定时间内处死实验动物，对神经组织进行切片。而这些侵袭性的方法，不能对神经干细胞在同一动物体内的迁徙、增殖情况进行动态的观察，故需要非侵袭的手段来对移植入体内的神经干细胞进行监测。     

MRI活体示踪大鼠脑内超顺磁性氧化铁标记成人神经干细胞

背景：目前判断神经干细胞移植后向脑损伤部位的迁移需要处死受体动物行脑切片检查,且不能进行多点、动态的观察。 目的：探讨用MRI活体示踪移植磁化标记成人神经干细胞在创伤性脑损伤模型大鼠脑内迁移和分布的可行性。 方法：建立大鼠脑部左侧半球创伤性脑损伤模型,超顺磁性氧化铁体外标记成人神经干细胞。模型建立后2周将标记成人神经干细胞立体定向移植入大鼠脑部右侧半球。在移植后1 d、3 d、1周和2周分别行大鼠头部MRI。2周后处死大鼠取脑,用普鲁士蓝染色法进行染色,观察标记神经干细胞的迁移。 结果与结论：超顺磁性氧化铁体外标记成人神经干细胞的成功率约为85%。移植后行头颅MRI可见位于右侧半球的移植部位FSE T2WI和GRE T2序列呈环形低信号。随时间推移,创伤性脑损伤后移植标记干细胞组大鼠头颅MRI可见脑内有一低信号线,指向对侧脑挫伤部位,而创伤性脑损伤后移植未标记干细胞组,正常大鼠移植标记干细胞组无信号线。MRI显像结果与脑切片普鲁士蓝染色观察到的结果是相符合的。 结果提示用MRI活体示踪移植磁化标记成人神经干细胞在创伤性脑损伤模型大鼠脑内迁移和分布可行、有效。     

超顺磁性氧化铁标记的骨髓间充质干细胞

背景：目前,超顺磁性氧化铁纳米颗粒标记的骨髓间充质干细胞在治疗心、肝、肾及中枢神经系统疾病方面已经得到了快速的应用。 目的：对国内外应用超顺磁性氧化铁标记骨髓间充质干细胞的现状及新进展作一综述。 方法：应用计算机检索CNKI和Pubmed数据库中2001-12/2009-12关于超顺磁性氧化铁标记骨髓间充质干细胞的文章,在标题和摘要中以“超顺磁性氧化铁,干细胞,标记,磁共振成像”或“superparamagnetic iron oxide,stem cells, label, magnetic resonance imaging”为检索词进行检索。选择近5年内文章内容与超顺磁性氧化铁标记骨髓间充质干细胞有关者,同一领域文献则选择近期发表或发表在权威杂志文章。初检得到243篇文献,根据纳入标准选择关于超顺磁性氧化铁标记骨髓间充质干细胞的40篇文献进行综述。 结果与结论：以往通过光镜识别干细胞标记物的研究中,必须用传统的组织病理学检查,从体内取得组织才能进行细胞探测,这显然不适合进行动态观察,更不适用于临床研究。超顺磁性氧化铁可以有效地进行活细胞标记,而这种标记方法不会影响细胞的活力、生长、分裂、迁移、分化等生物学功能,对细胞没有毒性,具有良好的安全性,可以用MRI进行活体示踪研究。     

纳米磁化标记神经干细胞的MRI大鼠活体示踪实验研究

目的:探讨用MRI活体示踪移植磁化标记神经干细胞在创伤性脑损伤模型大鼠脑内迁移和分布的可行性。方法:建立大鼠脑部左侧半球脑损伤模型。2周后将磁化标记胚胎神经干细胞立体定向移植入大鼠脑部右侧半球。在移植后1、3d及1、2周分别行大鼠头部MRI。结果:移植后行头颅MRI可见移植部位FSET2 WI和GRET2 序列呈环形低信号。实验组大鼠头颅MRI脑内有一低信号线,指向对侧脑挫伤部位。结论:用MRI活体示踪移植磁化标记神经干细胞在TBI模型大鼠脑内迁移和分布是可行的。     

USPIO标记大鼠骨髓源性神经干细胞移植脑皮层影像及形态学初步研究

目的将超小超顺磁性氧化铁（USPIO）Sinerem标记的大鼠骨髓源性神经干细胞移植鼠脑后，初步观察其在大脑中的活性、迁移和整合情况，确定MRI成像示踪Sinerem标记神经干细胞的可行性。方法分离SD大鼠骨髓基质细胞，体外培养诱导成骨髓源性神经干细胞。将Sinerem氧化铁和神经干细胞共孵育培养过夜。采用普鲁士蓝染色和透射电镜确定细胞内铁的摄取、定位情况。将标记细胞立体定向移植微注射到大鼠脑皮层。在不同时间点以SE序列T2WI行4．7T磁共振干细胞成像示踪，然后用组织学方法观察标记细胞在脑内的转归情况。结果Sinerem标记神经干细胞效率为98％～100％，普鲁士蓝染色显示铁颗粒存在胞质中，电镜显示铁颗粒集中于内涵体／溶酶体中；移植细胞体内的T2WI信号强度明显降低．可在4周时检测到细胞沿胼胝体迁移；组织学检测结果表明标记后的细胞可在脑内存活，并能沿神经纤维迁移。结论USPIO能有效地标记骨髓源性神经干细胞，利用磁共振成像可进行大脑中活体示踪监测。     

Resovist标记神经干细胞向大鼠局灶性脑缺血区域的迁移：MRI体内追踪

摘要 背景：Resovist是一种超顺磁性氧化铁,能够标记神经干细胞。本实验成功制备Resovist标记的神经干细胞（磁标记神经干细胞）,并利用MRI技术活体内追踪磁标记神经干细胞向大鼠脑部缺血区的迁移。 目的：利用核磁共振技术（MRI）活体追踪Resovist标记的神经干细胞移植治疗大鼠局灶性脑缺血。 设计,时间,地点：体外进行细胞学研究及大鼠脑内活体追踪试验。实验从2006年12月到2009年2月在哈尔滨医科大学基础实验室及哈尔滨医科大学附属第二医院神经科和MRI室完成。 材料：哈尔滨医科大学动物中心提供的新生清洁级SD大鼠 方法：神经干细胞培养、传代;制备Resovist标记的神经干细胞;利用免疫细胞化学、透射电镜和Prussian blue 染色等方法对Resovist标记神经干细胞的生长曲线进行研究。核磁共振追踪活体磁标记神经干细胞。 主要观察指标：免疫细胞化学、透射电镜、普鲁士蓝染色和MRI等方法 结果：在原代及传代细胞中有Nestin阳性细胞即神经干细胞。Resovist与神经干细胞共同孵育后,透射电镜及Prussian blue 染色显示胞浆中含有铁颗粒,铁颗粒也可以随细胞的分裂增殖而传到子代细胞中。随Resovist浓度的增高(2.8－11.2μg/ml), Resovist对神经干细胞存活无显著性影响。当Resovist的浓度大于22.4μg/ml时,影响其存活。活体状态下,MRI成功追踪到Resovist标记神经干细胞(Resovist浓度为 11.2μg/ml)呈低信号,并随时间推移,细胞向缺血灶迁移。 结论：本实验利用Resovist作为磁标记探针,成功制备磁标记神经干细胞。利用核磁共振（MRI）技术对磁标记神经干细胞进行活体追踪,观察细胞移植后的存活、迁移状况。     

不同种类超顺磁性氧化铁标记猪骨髓间充质干细胞的体外MR成像

背景：干细胞磁性标记是新近开展的一项干细胞体外标记技术,结合MR成像设备可以活体监控移植入体内的干细胞。 目的：明确超顺磁性氧化铁粒子体外标记猪骨髓间充质干细胞的方法、不同种类超顺磁性氧化铁标记细胞经MR成像的特征及可成像的最低标记细胞量。 设计、时间及地点：对比观察,于2006-09/ 2007-03在苏州大学医学部心血管外科实验室及苏州大学附属第一医院影像中心完成。 材料：猪髂骨骨髓由太湖梅山猪新鲜采集;超顺磁性氧化铁纳米颗粒为德国Schering公司产品;超微型超顺磁性氧化铁纳米颗粒由苏州大学化学与化工学院提供：铁颗粒晶核表面包被葡聚糖,3种超微型超顺磁性氧化铁包被葡聚糖后根据颗粒大小(12,15,20 nm)分别依次简称为1#,2#,3#。 方法：分离、纯化、培养猪骨髓间充质干细胞,体外进行不同种类超顺磁性氧化铁标记,染色及荧光显微镜观察;测量并绘制未标记细胞和标记细胞的MTT生长曲线;选取不同的细胞量组(Feridex标记细胞分别选取1×106、5×105及1×105 L-1量组,未标记细胞选取5×105 L-1量组,1#、2#及3#超微型超顺磁性氧化铁标记细胞均选取 5×105 L-1量组)进行标记后MR成像,测量不同扫描序列标记细胞管的信号强度改变,并进行统计学分析。 主要观察指标：超顺磁性氧化铁标记干细胞的普鲁士蓝染色检测标记率;标记干细胞的MTT生长曲线;双染色法检测细胞凋亡;不同Ependoff管内细胞团T1WI、T2WI和FFE图像的信号强度。 结果：应用多聚赖氨酸介导干细胞磁标记方法标记骨髓间充质干细胞有效率为100%,普鲁士蓝染色见细胞浆内有多少不等的蓝染铁颗粒;超顺磁性氧化铁标记的间充质干细胞在T2WI尤其是FFE(T2*WI)序列信号明显降低;在25 mg/L Fe培养液标记浓度下,MR成像的最低细胞量为1×105;在不同种类超顺磁性氧化铁标记下,2#、3#USPIO与Feridex在T2WI及T2*WI上有显著性差异 (P < 0.01);而1#USPIO与Feridex在T2WI及T2*WI上差异无显著性意义(P > 0.05);Feridex标记间充质干细胞在T2WI及T2*WI上与T1WI相比,差异均有显著性意义(P < 0.01)。 结论：超顺磁性氧化铁可以简便标记间充质干细胞并且在适当浓度下对间充质干细胞的生物学活性没有影响,MR T2WI和T2*WI序列可敏感显像磁性标记的干细胞。     

超顺磁性氧化铁在干细胞移植治疗神经系统疾病中的应用

正神经系统疾病中,无论是神经系统变性疾病和中枢神经系统炎性脱髓鞘病为主要特点的自身免疫系统疾病,还是以脑缺血、脑出血为高发的急性脑血管疾病,其所造成的神经功能缺损及严重认知功能障碍一直是临床治疗的难点,严重威胁着人类的健康和生活,且致死率和致残率较高,给患者本人、家庭和整个社会带来沉重的负担~([1-5])。然而,随着再生医学的发展,干细胞移植治疗神经系统疾病的探讨已成为当今神经科学领域研究的热点~([3,6-9])。但     

超顺磁性氧化铁标记骨髓间充质干细胞的体外标准化实验

超顺磁性氧化铁颗粒标记成像可在体观察标记细胞移植后情况,但结合临床细胞治疗剂量,其标记浓度及标记时间对细胞标记率、标记活性及标记后成像效果的综合影响还需进一步分析。 目的：筛选超顺磁性氧化铁体外标记大鼠骨髓间充质干细胞的标准化剂量,拟为体内成像提供最佳标记“浓度-时间”。 设计、时间及地点：细胞学体外对照观察,于2008-02/10在山西医科大学完成。 材料：清洁级Wistar大鼠10只,由山西医科大学动物实验中心提供。Resovist中含超顺磁性氧化铁铁颗粒28 g/L,为德国Schering公司产品。 方法：全骨髓法分离培养大鼠骨髓间充质干细胞。取Resovist,分别配制含终浓度为0,25,50,75,100,150 mg/L超顺磁性氧化铁的培养基,加入P3代骨髓间充质干细胞中进行孵育标记。 主要观察指标：普鲁士蓝法检测细胞标记率,锥虫蓝拒染法检测标记细胞活性,观察标记细胞体外磁共振成像情况。 结果：细胞标记率达100%,随着标记时间的延长,胞质内蓝染颗粒逐渐减少。标记1 d和3 d时,与0 mg/L超顺磁性氧化铁组比较,25,50 mg/L组锥虫蓝拒染率无明显差异(F=0.28~3.15,P > 0.05);与25 mg/L超顺磁性氧化铁组比较,50 mg/L组锥虫蓝拒染率无明显差异(F=0.28~0.79,P > 0.05)。体外磁共振成像示标记3 d时,标记浓度为50 mg/L组的T2WI及T2*WI信号降低最明显。 结论：超顺磁性氧化铁“50 mg/L-3 d”体外标记效率高,对细胞活性无影响,且磁共振成像信号降低最明显,为最适“浓度-时间”组合。     

超顺磁性氧化铁体外标记大鼠骨髓基质干细胞的传代：细胞中铁粒子会随传代而变化吗？*★

背景：超顺磁性氧化铁作为磁共振对比剂已进行了大量临床实验，但其随标记细胞传代分化后的分布及代谢却报道甚少。 目的：实验首次观察和描述了体外超顺磁性氧化铁标记的大鼠骨髓基质干细胞及其传代细胞的情况，并以磁共振信号检测铁粒子随细胞传代的演变情况。 设计、时间及地点：细胞学体外观察，于2006-06/2007-01在川北医学院附属医院医学影像研究所和风湿免疫研究所完成。 材料：清洁级雌性大白鼠2只，由川北医学院动物中心提供。超顺磁性氧化铁由德国先灵公司惠赠。 方法：抽取大鼠双侧股骨和胫骨的骨髓，采用贴壁法分离纯化骨髓基质干细胞，用铁浓度为42 mg/L的氧化铁-多聚赖氨酸复合物600 μL进行体外标记。 主要观察指标：倒置显微镜下观察各代细胞标记阳性率，磁共振扫描测定磁共振信号强度变化百分率。 结果：普鲁士蓝染色后，镜下第1代细胞超顺磁性氧化铁标记阳性率为100%，随着传代次数的增加，第1~5代细胞标记阳性率逐级降低。与未接受超顺磁性氧化铁标记的PBS对照比较，除第1，2代细胞信号强度变化率无明显变化外，随着细胞的传代磁共振信号强度变化百分率逐渐降低，细胞标记率与T2*WI信号强度呈负性相关(r=-0.986 6，P < 0.005)。 结论：标记入骨髓基质干细胞内的铁能随细胞的传代而传向子代，并可以在一定时期内用磁共振进行追踪检测，实验结果亦首次提出了磁标记的细胞铁粒子可随细胞传代而递减的规律。     

SPIO标记神经干细胞治疗小脑萎缩大鼠的实验研究

目的探讨超顺磁性氧化铁（SPIO）标记胎鼠神经干细胞（NSC）的脑内MRI示踪效果及NSC对小脑萎缩大鼠共济运动的影响。方法将24只小脑萎缩大鼠模型随机等分为对照组、标记组、未标记组及灭活标记组,每组6只,用生理盐水、SPIO标记NSC、未标记NSC及灭活的NSC悬液分别注射于各组大鼠的小脑齿状核;进行步距行为学检测、活体MRI示踪扫描、脑组织切片普鲁士蓝染色,观察移植NSC的分布。结果与对照组、灭活标记组比较,标记组、未标记组大鼠移植后步距行为学明显改善（P〈0.05）;与灭活标记组比较,标记组MRI显示移植4周后移植区低信号影响范围较广,普鲁士蓝染色阳性细胞向周围迁移距离较远。结论MRI可显示SPIO标记的NSC在移植大鼠脑内的分布和存活情况;移植NSC能改善小脑萎缩大鼠的共济运动功能。     

人胚神经干细胞移植治疗大鼠脑缺血的实验研究

目的　研究人胚神经干细胞(hNSCs)移植治疗脑缺血大鼠的效果及其在缺血大鼠脑内的状况。方法　从自然流产的孕10~13周的人胚脑组织中分离、培养神经干细胞。采用线栓法制作大鼠脑缺血模型,1d后经尾静脉移植未分化的hNSCs入脑缺血大鼠体内,对移植后大鼠进行神经损害严重程度评分(NSS),用免疫组化方法观察移植后hNSCs的存活、迁徙、分化状况。结果　从人胎脑中成功培养出hNSCs,培养条件下呈悬浮状态生长,形成神经球,绝大多数的细胞表达神经干细胞的标记物神经巢蛋白(nestin)。hNSCs移植组大鼠自移植后3周末起其NSS显著低于对照组(P<0 .05);移植后2、3、4、5周脑组织切片中均可见5 溴脱氧嘧啶尿苷(Brdu)染色阳性细胞,缺血侧明显多于对侧(P<0 .05),移植后3、4、5周末明显多于移植后2周(均P<0 .05);移植组各时间点脑组织切片中均可见nestin染色阳性细胞;在Brdu阳性细胞群中, 73 8%为胶质纤维酸性蛋白(GFAP)染色阳性的星形胶质细胞, 16 7%为2, 3 环核苷酸磷酸二脂酶(CNPase)染色阳性的少突胶质细胞, 9 5%为神经元特异性烯醇化酶(NSE)染色阳性的神经元。结论　经静脉移植hNSCs能有效改善脑梗死动物的神经功能,hNSCs体内体外均具有多向分化潜能,受缺血部位微环境信号的影响分化成3种主要类型的神经细胞。     

Human embryonic neural stem cell transplantation increases subventricular zone cell proliferation and promotes peri‐infarct angiogenesis after focal cerebral ischemia

Neurogenesis and angiogenesis are two important processes that may contribute to the repair of brain injury after stroke. This study was designed to investigate whether transplantation of human embryonic neural stem cells (NSCs) into cortical peri‐infarction 24 h after ischemia effects cell proliferation in the subventricular zone (SVZ) and angiogenesis in the peri‐infarct zone. NSCs were prepared from embryonic human brains at 8 weeks gestation. Focal cerebral ischemia was induced by permanent occlusion of the middle cerebral artery of adult rats. Animals were randomly divided into two groups (n = 30, each) at 24 h after ischemia: NSC‐grafted and medium‐grafted groups. Toluidine blue staining and 5′‐bromo‐2′‐deoxyuridine (BrdU) or von Willebrand factor (vWF) immunohistochemistry were performed at 7, 14 and 28 days after transplantation. NSC transplantation increased the number of BrdU‐positive cells in the ischemic ipsilateral SVZ compared with the medium control at 7 days (P < 0.01). This difference in SVZ cell proliferation persisted at 14 days (P < 0.01), but was not significant at 28 days (P > 0.05). In addition, angiogenesis, as indicated by BrdU and vWF staining in cortical peri‐infarct regions, was augmented by 46% and 65% in NSC‐grafted rats versus medium‐grafted rats at 7 and 14 days, respectively (P < 0.05). However, this increase became non‐significant at 28 days (P > 0.05). Our results indicate that NSC transplantation enhances endogenous cell proliferation in the SVZ and promotes angiogenesis in the peri‐infarct zone, even if it is performed in the acute phase of ischemic injury.     

Stem cell transplantation for treatment of cerebral ischemia in rats Effects of human umbilical cord blood stem cells and human neural stem cells

BACKGROUND:Exogenous neural stem cell transplantation promotes neural regeneration. However, various types of stem cells transplantation outcomes remain controversial. OBJECTIVE:To explore distribution, proliferation and differentiation of human neural stem cells (hNSCs) and human umbilical cord blood stem cells (hUCBSCs) following transplantation in ischemic brain tissue of rats, and to compare therapeutic outcomes between hNSCs and hUCBSCs. DESIGN, TIME AND SETTING:Randomized controlled animal studies were performed at the Experimental Animal Center of Nanjing Medical University and Central Laboratory of Second Affiliated Hospital of Nanjing Medical University of China from September 2008 to April 2009. MATERIALS:hNSCs were harvested from brain tissue of 10-13 week old fetuses following spontaneous abortion, and hUCBSCs were collected from umbilical cord blood of full-term newborns at the Second Affiliated Hospital of Nanjing Medical University of China. hNSCs and hUCBSCs were labeled by 5-bromodeoxyuridine (BrdU) prior to transplantation. METHODS:Rat models of cerebral ischemia were established by the suture method. A total of 60 healthy male Sprague Dawley rats aged 7-9 weeks were randomly assigned to hNSC transplantation, hUCBSC transplantation and control groups. The rat models in the hNSC transplantation, hUCBSC transplantation and control groups were infused with hNSC suspension, hUCBSC suspension and saline via the caudal vein, respectively. MAIN OUTCOME MEASURES:The distribution, proliferation and differentiation of hNSCs and hUCBSCs in ischemic brain tissue were observed using immunohistochemical methods. Neurological function in rats was assessed using the neurological severity score. RESULTS:The number of BrdU-positive cells was significantly greater in the hNSC transplantation group compared with hUCBSC transplantation group at 14 days following transplantation (P < 0.05). The number of BrdU-positive cells reached a peak at 28 days following transplantation. Nestin-positive, glial fibrillary acidic protein-positive, cyclic nucleotide 3' phosphohydrolase-positive and neuron specific enolase-positive cells were visible following transplantation. No significant difference was determined in the constituent ratio of various cells between hNSC and hUCBSC transplantation groups (P > 0.05). The neurological severity score was significantly decreased in rats at 21 days following transplantation (P < 0.05). No significant difference was detected in neurological severity score between hNSC and hUCBSC transplantation groups at various time points (P > 0.05). CONCLUSION:The transplanted hNSCs and hUCBSCs can migrate into ischemic brain tissue, proliferate and differentiate into neuron-like, astrocyte-like and oligodendrocyte-like cells, and improve neurological function in rats with cerebral ischemia.     

Application of magnetic resonance imaging for monitoring stem cell transplantation for the treatment of cerebral ischemia

OBJECTIVE:To identify global research trends in the application of MRI for monitoring stem cell transplantation using a bibliometric analysis of Web of Science.DATA RETRIEVAL:We performed a bibliometric analysis of studies relating to the application of MRI for detecting stem cell transplantation for the treatment of cerebral ischemia using papers in Web of Science published from 2002 to 2011.SELECTION CRITERIA:The inclusion criteria were:(a) peer-reviewed articles on the application of MRI for detecting transplanted stem cells published and indexed in Web of Science;(b) year of publication between 2002 and 2011.Exclusion criteria were:(a) articles that required manual searching or telephone access;(b) some corrected papers.MAIN OUTCOME MEASURES:(1) Annual publication output;(2) distribution according to journals;(3) distribution according to institution;(4) distribution according to country;(5) top cited authors over the last 10 years.RESULTS:A total of 1 498 studies related to the application of MRI for monitoring stem cell transplantation appeared in Web of Science from 2002 to 2011,almost half of which were derived from American authors and institutes.The number of studies on the application of MRI for detecting stem cell transplantation has gradually increased over the past 10 years.Most papers on this topic appeared in Magnetic Resonance in Medicine.CONCLUSION:This analysis suggests that few experimental studies have been investigated the use of MRI for tracking SPIO-labeled human umbilical cord blood-derived mesenchymal stem cells during the treatment of cerebral ischemia.     

不同MR扫描序列对脑内移植SPIO标记神经干细胞大鼠的成像对比研究

目的比较3种不同MR扫描序列对脑内移植的超顺磁性氧化铁(SPIO)示踪标记神经干细胞显示作用的优劣,找出最佳扫描方案.方法将SPIO标记的神经干细胞移植到大鼠脑内,制备动物移植模型.行MR扫描,扫描序列包括SE T2WI(TR 6 000 ms,TE 100ms)、FSE T2WI(TR 2 200ms,TE 90 ms)和GRE T2*WI(TR 500ms,TE 30 ms),分析3种扫描序列在SPIO标记神经干细胞移植大鼠脑的显像特征,并进行病理学检查对照分析.结果3种扫描序列均示靶点(标)信号强度较靶点(未)有不同程度的下降,而且靶点(标)的信号强度衰减率(PSIL)在GRE T2*WI明显高于其他序列,SE T2WI、FSE T2WI中靶点(标)之间PSIL没有显著性差异;3种扫描序列中靶点(未)的信号与正常脑组织信号没有显著性差别.结论SPIO标记的神经干细胞移植到大鼠脑内后,3种MRI扫描序列显像中以GRET2*WI最为敏感.     

Electroacupuncture improves neurological deficits and enhances proliferation and differentiation of endogenous nerve stem cells in rats with focal cerebral ischemia

Abstract

Objectives: This study was carried out to observe the effect of electroacupuncture (EA) on neurological deficits, proliferation and differentiation of nerve stem cells (NSCs) in adult rats with middle cerebral artery occlusion (MCAO) and to study its possible role in the treatment of cerebral ischemic injury.

Methods: A rat model of MCAO was established and interfered with EA. On days 4, 7, 14 and 21 after ischemic injury, neurological deficits were scored. On days 4, 7, 14 and 21 after injury, effect of EA interference on the proliferation and differentiation of rat NSCs was observed with BrdU/NeuN and BrdU/GFAP immunofluorescence double labeling.

Results: A significant difference was found in the scores of rat neurological deficits between the EA and model groups 7, 14 and 21 days after cerebral ischemic injury (p<0·05). BrdU positive cells were found in the subventricular zone (SVZ) 4, 7, 14 and 21 days after ischemic injury. The number of positive BrdU cells in the SVZ reached its peak 7 days after injury and was greater in the EA group than in the model group 7 and 14 days after injury (p<0·05). The number of BrdU/GFAP doubly labeled positive cells in the SVZ was greater in the EA group than in the model group 7 and 14 days after ischemic injury (p = 0·012 and p = 0·025, respectively). There was no difference in the number of BrdU/NeuN doubly labeled positive cells 4, 7 and 14 days in the striatum, but a significant difference 21 days (p = 0·033) after ischemic injury between the two groups.

Discussion: Cerebral ischemic injury induces proliferation of NSCs, some of which will differentiate into both astroglia and neurons. EA may promote cells proliferation, stimulate the proliferating cells to differentiate into astroglia and mature into neurons, which may be one of the important reasons why EA can alleviate neurological deficits.     

Magnetic resonance imaging tracing of transplanted bone marrow mesenchymal stem cells in a rat model of cardiac arrest-induced global brain ischemia

BACKGROUND： Numerous studies have shown that magnetic resonance imaging （MRI） can detect survival and migration of super paramagnetic iron oxide-labeled stem cells in models of focal cerebral infarction. OBJECTIVE： To observe distribution of bone marrow mesenchymal stem cells （BMSCs） in a rat model of global brain ischemia following cardiac arrest and resuscitation, and to investigate the feasibility of tracing iron oxide-labeled BMSCs using non-invasive MRI. DESIGN, TIME AND SETTING： The randomized, controlled, molecular imaging study was performed at the Linbaixin Medical Research Center, Second Affiliated Hospital, Sun Yat-sen University, and the Institute of Cardiopulmonary Cerebral Resuscitation, Sun Yat-sen University, China from October 2006 to February 2009. MATERIALS： A total of 40 clean, Sprague Dawley rats, aged 6 weeks and of either gender, were supplied by the Experimental Animal Center, Sun Yat-sen University, China, for isolation of BMSCs. Feridex （iron oxide）, Gyroscan Inetra 1.5T MRI system, and cardiopulmonary resuscitation device were used in this study. METHODS： A total of 30 healthy, male Sprague Dawiey rats, aged 6 months, were used to induce ventricular fibrillation using alternating current. After 8 minutes, the rats underwent 6-minute chest compression and mechanical ventilation, followed by electric defibrillation, to establish rat models of global brain ischemia due to cardiac arrest and resuscitation. A total of 24 successful models were randomly assigned to Feridex-labeled and non-labeled groups （n = 12 for each group）. At 2 hours after resuscitation, 5 ×10^8 Feridex-labeled BMSCs, with protamine sulfate as a carrier, and 5 ×10^6 non-labeled BMSCs were respectively transplanted into both groups of rats through the right carotid artery （cells were harvested in 1 mL phosphate buffered saline）. MAIN OUTCOME MEASURES： Feridex-labeled BMSCs were observed by Prussian blue staining and electron microscopy. Signal intensity, celluar viability, and proliferative capacity of BMSCs were measured using MRI, Trypan blue test, and M-IT assay, respectively. Distribution of transplanted cells was observed in rats utilizing MRI and Prussian blue staining prior to and 1, 3, 7, and 14 days after transplantation. RESULTS： Prussian blue staining displayed many blue granules in the Feridex-labeled BMSCs. High density of iron granules was observed in the cytoplasm under electron microscopy. According to MRI results, and compared with the non-labeled group, the signal intensity was decreased in the Feridex-labeled group （P 〈 0.05）. The decrease was most significant in the 50 pg/mL Feridex-labeled group （P 〈 0.01）. There were no significant differences in celluar viability and proliferation of BMSCs between the Feridex-labeled and non-labeled groups after 1 week （P 〉 0.05）. Low-signal lesions were detected in the rat hippocampus and temporal cortex at 3 days after transplantation. The low-signal lesions were still detectable at 14 days, and positively stained cells were observed in the hippocampus and temporal cortex using Prussian blue staining. There were no significant differences in signal intensity in the non-labeled group. CONCLUSION： BMSC transplantation traversed the blood-brain barrier and distributed into vulnerable zones in a rat model of cardiac arrest-induced global brain ischemia. MRI provided a non-invasive method to in vivo dynamically and spatially trace Feridex-labeled BMSCs after transplantation.     

rTMS促进大鼠局灶性脑缺血海马内源性神经干细胞分化的研究

目的探讨重复经颅磁刺激（rTMS）对局灶性脑缺血大鼠海马内源性神经干细胞分化的影响。方法线栓法制备大鼠大脑中动脉闭塞（MCAO）模型,随机分为脑缺血自然恢复组和rTMS治疗组,用荧光显微镜和共聚焦显微镜观察缺血14d、28d后各组大鼠海马中5-溴脱氧尿核苷（BrdU）与神经元特异核蛋白（NeuN）、神经胶质酸性蛋白（GFAP）共同标记的阳性细胞,并在高倍荧光显微镜下对双标阳性细胞计数。结果脑缺血后14d、28d,rTMS治疗组大鼠海马BrdU／NeuN双标阳性细胞数量分别为17．12±2．91、23．20±5．97,较相应自然恢复组12．96±2．79、15．92±2．52明显增加,两组同一时间点组间比较有统计学差异（P〈0．01）。而脑缺血后14d、28d,rTMS治疗组大鼠海马BrdU／GFAP双标阳性细胞数量分别为30．48±4．58、36．48±4．90,较相应自然恢复组37．44±3．58、43．60±5．96减少,两者相比有统计学差异（P〈0．05）。结论局灶性脑缺血大鼠海马增殖的内源性神经干细胞,可分化为神经元或神经胶质细胞,而rTMS可促进海马内源性神经干细胞向神经元的分化。     

嗅鞘细胞联合神经干细胞移植治疗小儿脑发育不全

背景：近年来,干细胞替代治疗为神经再生提供了新的方法,但干细胞移植治疗小儿脑发育不全的相关报道甚少。 目的：验证嗅鞘细胞联合神经干细胞移植治疗小儿脑发育不全的有效性。 方法：2009-10解放军第163医院收治了1例脑发育不全的患者,给予物理降温、神经营养、维持水电解质平衡、高压氧治疗的同时,以L3~4腰椎间隙为穿刺点,将配置好的神经干细胞约8×107个和嗅鞘细胞约4×107个缓慢注入蛛网膜下腔,每2周1次,2次为 1 个疗程,共治疗1个疗程。从体温恢复程度、双手精细动作、运动协调性、语言等方面来评价移植治疗效果。 结果与结论：与移植前比较,嗅鞘细胞联合神经干细胞移植1个月后患儿体温恢复正常,四肢肌力明显下降,2个月后可以独自端坐,3个月后可以扶梯行走,有简单的语言表达。提示嗅鞘细胞联合神经干细胞移植治疗小儿脑发育不全是有效的,能恢复其中枢神经功能。