磁标记大鼠神经干细胞移植入脑缺血大鼠的磁共振示踪

[目的]使用菲立磁（Feridex）体外标记胎鼠神经干细胞（neural stem cells,NSCs）,并在移植脑缺血大鼠后进行活体MRI示踪观察。[方法]分离、培养大鼠胚胎源性神经干细胞,使用“Feridex-多聚赖氨酸复合物（FE-PLL）” ,标记神经干细胞,对标记细胞分别进行普鲁士蓝染色、电镜观察,将FE-PLL标记神经干细胞分别移植人脑缺血大鼠左右侧脑室内,活体移植后1、5、14d体内MRI示踪。[结果]菲立磁可以高效率地标记神经干细胞,普鲁士蓝染色显示FE-PLL标记神经干细胞胞质内出现细小的蓝色铁颗粒。电镜结果显示FE-PLL标记的神经干细胞胞质内含有许多包裹铁颗粒的囊泡。MRI检查发现脑内移植的标记细胞在磁共振上呈明显的低信号改变。[结论]菲立磁可以用来体外标记神经干细胞,利用MRI技术可以对脑内移植后的标记细胞进行初步的活体追踪。     

超顺磁性氧化铁标记脂肪干细胞移植入大鼠心脏后的活体磁共振示踪成像

目的 探讨超顺磁性氧化铁(SPIO)标记脂肪干细胞(ADSCs)移植入大鼠心脏后的活体磁共振成像(MRI)示踪的可行性.方法 使用左旋多聚赖氨酸-SPIO共培养方式标记ADSCs.采用普鲁士蓝染色及透射电镜观察细胞内铁颗粒,台盼兰染色检测细胞活力,并对标记的干细胞进行体外MRI成像.将经过SPIO标记的干细胞移植入正常大鼠心脏,使用MRI进行活体成像观察并与病理结果进行对照分析.结果 普鲁士蓝染色于ADSCs胞浆内可见蓝色颗粒,电镜检查见铁颗粒位于内涵体/溶酶体内;台盼兰染色检测细胞活力实验组与对照组差异无显著性(P>0.05);标记了SPIO的干细胞体外MRI成像时,实验组信号显著低于阴性对照组和空白对照组;标记后的干细胞移植到心脏后,MRI显示细胞移植区域信号缺失,对应区域病理切片普鲁士蓝染色可见胞浆内染色阳性的细胞.结论 MRI可以对移植入心脏的经SPIO标记的干细胞进行无创、动态的活体示踪成像,有助于了解移植细胞在体内的存活及迁徙情况.     

磁性纳米粒标记的神经干细胞不同移植途径对大鼠脑损伤治疗的实验研究

目的 探讨脑损伤后不同移植途径神经干细胞的迁移及分布情况并进行对比研究.方法 体外培养的胚胎神经干细胞,采用Feeney自由落体脑创伤模型制成大鼠脑损伤模型,超顺磁性氧化铁纳米颗粒(SPIO)标记神经干细胞,并将其分别经枕大池穿刺注射入脑损伤大鼠蛛网膜下腔的脑脊液中及经立体定向脑内注射移植,分别进行大鼠运动功能缺失的神经功能评价、磁共振示踪及大鼠脑切片普鲁士蓝染色.结果 接受神经干细胞移植的两组大鼠神经运动功能评分均较损伤对照组明显提高(P<0.05),两移植组大鼠神经运动功能评分无明显差别.接受神经干细胞移植的两组大鼠神经运动功能评分均较损伤对照组明显提高(P<0.05),两移植组大鼠神经运动功能评分无明显差别.标记组移植经枕大池移植的神经干细胞即刻的MRI即可观察到大鼠脑内的移植标记细胞,移植后2周脑挫伤即可见到低信号影,组织切片的普鲁士蓝染色与MRI结果相符.结论 经枕大池移植的神经干细胞具有远距离迁移能力,并能像脑内移植一样明显有助于大鼠神经运动功能的恢复.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.     

胎鼠神经干细胞移植对大鼠脊髓损伤后神经红蛋白及半胱氨酸蛋白酶-3表达的影响

目的研究胎鼠神经干细胞(NSCs)移植对大鼠脊髓损伤(SCI)后神经红蛋白(Ngb)及半胱氨酸蛋白酶-3(caspase-3)表达的影响。方法 40只SD大鼠随机分为正常对照组(Normal组)、脊髓损伤组(SCI组)、神经干细胞组(NSCs组)、神经干细胞标记组(BrdU+NSCs组)。采用电控SCI打击装置制作模型,5-溴脱氧尿嘧啶核苷(BrdU)法标记处于对数生长期的NSCs,SCI后即刻进行NSCs移植。免疫组化法观察BrdU标记NSCs的存活、迁移及Ngb和caspase-3的表达,改良Rivlin法观察大鼠后肢运动功能的恢复情况。结果 BrdU+NSCs组在损伤脊髓区域可检测到BrdU标记的阳性NSCs。BrdU+NSCs组和NSCs组各时间点caspase-3免疫阳性细胞光密度值均比SCI组减少(P<0.01),Ngb免疫阳性细胞光密度值比SCI组明显增加(P<0.01),且Ngb表达高峰延长至伤后第14天;移植后第7、14、28天,后肢运动功能评分比SCI组明显升高(P<0.01)。BrdU+NSCs组与NSCs组之间比较差异无统计学意义(P>0.05)。结论体外培养的胚胎大鼠NSCs可在SCI区域存活、迁移,并能通过上调Ngb的表达来抑制大鼠SCI后神经细胞的凋亡,从而促进大鼠瘫痪肢体功能的恢复。     

应用MRI活体示踪干细胞心肌移植可行性的实验研究

目的：探讨应用MRI活体示踪干细胞心肌移植的可行性.方法：选择8只雌性家猪,体重35～45 kg,经导管应用球囊封堵前降支动脉建立心肌梗死模型后,将存活的7只随机分为Feridex标记的干细胞移植组（n=4）和Feridex未标记的干细胞移植组（n=3）.建立模型2周后开胸,在梗死区中央及梗死边缘区共5个点注射骨髓间充质干细胞（BMSC）（1.25～7.54×10^6）.于移植前及移植后1 h、1周、2周分别行心脏MRI 检查,比较移植前后MRI心脏影像学变化.移植后2周,取心脏组织行HE染色和普鲁士蓝染色.结果：移植后1 h,Feridex标记的干细胞移植组中4只动物（100%）间充质干细胞移植区在MRI上呈明显的低信号改变,术后1周示心脏低信号改变达100%（4只动物）,术后2周示2只动物（50%）细胞移植区有低信号改变.病理检查示梗死区内大量炎性细胞浸润,Feridex标记的干细胞移植组心脏注射点处的组织普鲁士蓝染色阳性.结论：Feridex标记的干细胞在MRI上呈低信号改变,应用MRI活体示踪BMSC是可行的.     

神经干细胞移植联合腹腔注射促红细胞生成素对横断性脊髓损伤大鼠神经轴突的修复作用

目的: 探讨神经干细胞(NSCs)与促红细胞生成素(EPO)共同作用于横断性脊髓损伤大鼠后对损伤区轴突的修复作用,为临床治疗脊髓损伤提供理论依据。方法: 40只雌性成年Wistar大鼠,建立T10全横断大鼠脊髓损伤模型后,随机分为对照组、NSCs组、EPO组和联合治疗组,每组10只。术后8周采用BDA皮质脊髓束顺行追踪法和荧光金(FG)皮质脊髓束逆行追踪法评估损伤区脊髓神经轴突再生情况,同时分期采用实验性脊髓损伤运动功能BBB评分法评价大鼠后肢功能恢复情况。结果: BDA 免疫荧光染色和FG免疫荧光染色,联合治疗组可见大量被BDA-cy3红色荧光标记的再生轴突,其中部分再生轴突穿越损伤区到达远端;NSCs组仅见少量轴突再生,无神经轴突通过脊髓损伤区;EPO组偶见散在的神经纤维再生;对照组无明显的轴突再生。联合治疗组大脑皮质中可见少量被FG标记的椎体细胞及轴突发出金黄色荧光,其余3组大脑皮质中无FG标记细胞。大鼠后肢功能BBB评分,在术后1周及1周以后各时段,联合治疗组大鼠BBB评分均高于其他各组(P<0.05)。结论: 脊髓损伤后移植NSCs联合腹腔注射EPO可有效促进脊髓损伤区神经轴突的再生以及脊髓损伤大鼠后肢运动功能的恢复。     

Ferumoxide标记Flk1＋＋CD31＋-CD34-人骨髓间充质干细胞及其在食蟹猴脑内移植示踪观察

目的探讨Ferumoxide-PLL标记Flk1 CD31-CD34-人骨髓间充质干细胞(hBMSC)的方法及其在食蟹猴脑实质内移植活体示踪的可行性。方法采用Ferumoxide-PLL标记hBMSC,台盼蓝染色、普鲁士蓝染色和透射电镜扫描鉴定标记效率及细胞活力。体外磁共振成像(MRI)分别扫描标记和未标记细胞,计算T2*的弛豫时间和弛豫率(R2*)变化。通过立体定向手术将标记的hBMSC移植入食蟹猴右侧基底节区,采用MRI扫描活体示踪细胞。采用免疫组织化学、普鲁士蓝和HE染色对脑组织切片进行干细胞存活、分化及病理学研究。结果Ferumoxide-PLL标记hBMSC效率为96%,普鲁士蓝染色、电镜可显示标记hBMSC细胞质内铁颗粒。1×106和5×105两组Ferumoxide-PLL标记细胞的T2*的弛豫时间分别为68.86和79.88ms,而未标记细胞分别为12.71和15.24ms。标记细胞的R2*分别为78.68和65.61/s,分别是未标记细胞(14.52和12.52/s)的5.4和5.2倍。移植后3周MRI扫描T2WI仍可发现hBMSC呈明显的低信号。病理及免疫荧光结果显示hBMSCs在移植区大量存活,移植区有大量新生血管,但未见hBMSC向神经细胞分化。结论Ferumoxide-PLL可高效标记hBMSC,能显著增加其MRI图像对比度。MRI可活体示踪干细胞。移植入食蟹猴脑内的hBMSC可大量存活并促进新生血管形成。     

磁共振活体监测大鼠间充质干细胞移植治疗急性肾功能衰竭

目的 磁共振活体监测移植入急性肾功能衰竭(ARF)大鼠腹主动脉的磁标记间充质干细胞(MSCs)并检测大鼠.肾功能及肾脏病理改变.方法 磁性纳米粒子体外标记大鼠骨髓MSCs.ARF大鼠分为3组,插导管至腹主动脉,分别移植入标记细胞(10只);移植入未标记细胞(10只);灌注等量生理盐水(10只).移植后0.5 h及第1、2、5天应用MRI对移植细胞进行活体示踪,并与肾脏普鲁士蓝染色及CD68抗体染色对照.监测大鼠肾功能恢复及肾脏病理变化情况.结果 Fe2O3-PLL可有效标记大鼠MSCs.标记细胞移植后ARF大鼠.肾脏皮质区T2*WI信号强度明显下降,持续到移植后第5天.组织学分析见标记细胞分布于肾皮质肾小球内.细胞移植组肾功能优于对照组,肾损伤程度明显轻于对照组.结论 临床应用型1.5 T磁共振仪可活体监测移植入ARF大鼠腹主动脉的MSCs,移植后早期细胞分布于肾皮质肾小球内;MSCs移植后早期可促进ARF恢复.     

HIF-1α基因转导的神经干细胞移植对大鼠红核神经元逆行性损伤的保护作用

目的研究低氧诱导因子-1α(HIF-1α)基因转导的神经干细胞(NSCs)移植对大鼠脊髓损伤(SCI)后红核神经元损伤的影响。方法采用电控SCI打击装置制作大鼠SCI模型。将80只SD大鼠随机分为4组:对照组、SCI组、NSCs组、基因修饰移植组(HIF-NSC组)。5-溴脱氧尿嘧啶核苷(BrdU)法标记处于对数生长期的NSCs,SCI后即刻进行NSCs及HIF-1α基因转导的NSCs移植。应用免疫组化法观察BrdU标记的移植细胞的存活、迁移情况以及HIF-1α的表达,用辣根过氧化物酶(HRP)逆行示踪技术标记红核神经元,用四甲基联苯胺(TMB)呈色反应显示红核脊髓束神经元的存活情况,采用斜板试验(改良Rivlin法)观察大鼠后肢运动功能的恢复情况。结果 NSCs组与HIF-NSC组在损伤脊髓区域均可检测到BrdU标记的阳性NSCs;HIF-NSC组中HIF-1α免疫阳性细胞平均光密度(OD)值比其他各组各时间点均高(P<0.01),且表达高峰延迟至移植后14d;中脑HRP标记红核神经元数目明显多于NSCs组、SCI组(P<0.01);移植后第7、14、28天,HIF-NSC组后肢运动功能评分比NSCs组、SCI组明显升高(P<0.01)。结论 HIF-1α基因体外转导的胚鼠NSCs移植到SCI区域后可以存活、迁移,且能明显的上调HIF-1α的表达、减轻红核神经元的逆行性损伤,从而促进大鼠后肢运动功能的恢复。     

氯化锂联合脐血干细胞移植修复大鼠脊髓损伤

目的 观察氯化锂联合脐血干细胞移植对大鼠脊髓全横断损伤的修复效果.方法 成年雌性SD大鼠80只,建立胸9脊髓全横断损伤模型,随机分对照组(A组,n=20)、氯化锂组(B组,n=20)、细胞移植组(C组,n=20)和氯化锂+细胞移植组(D组,n=20).于术后1 d、3 d及每周的最后1天,应用BBB评分评价大鼠脊髓功能的恢复情况;8周后取材,通过Brdu细胞核标记观察移植细胞的存活、迁移;通过荧光金逆行追踪,观察脊髓神经纤维的再生与分布.结果 4只大鼠死亡.术后8周可观察到Brdu标记的脐血干细胞在体内存活并在脊髓内迁移;细胞移植组和氯化锂+细胞移植组可见少量连续性神经纤维通过损伤区.荧光金逆行脊髓追踪显示C组和D组可见被荧光金标记的神经锥体细胞穿越损伤区.术后8周A、B、C、D四组后肢功能运动BBB评分分别为4.11+0.14、4.50+0.15、8.31±0.11、11.15±0.18.结论 氯化锂能促进人脐血间充质干细胞在损伤区的存活并向神经细胞分化,氯化锂联合脐血干细胞与脊髓去细胞支架移植能够促进细胞移植修复大鼠脊髓损伤的效果.     

羊膜间充质干细胞静脉移植治疗脊髓损伤的实验

目的:探讨羊膜间充质干细胞静脉移植对脊髓损伤修复的影响。方法:90只成年SD大鼠按改良Allen′s打击方法建立脊髓损伤模型,随机分为3组:对照组、假移植组和移植组,每组30只。于脊髓损伤后1周经尾静脉移植Brdu标记的羊膜间充质干细胞。3组大鼠分别于损伤后第1 d、3 d、1周及移植后1 d、3 d、1周、2周、4周采用BBB评分法对行为学进行评价。并于移植后1 d、3 d、1周、2周、4周分批处死,切片观察Brdu标记的细胞能否迁移到损伤区。结果:脊髓损伤后第1 d,3组实验动物后肢运动功能BBB评分皆为0分;细胞移植1周后移植组动物BBB评分为5.6±0.6,对照组和假移植组动物BBB评分分别为5.3±0.4和5.2±0.6;细胞移植2周后移植组、假移植组和对照组BBB评分分别为11.3±0.9、6.4±0.5和6.5±0.8;4周后3组实验动物评分分别为13.4±0.9、8.3±0.6和8.5±0.7;在损伤部位出现了Brdu标记的羊膜间充质干细胞。结论:经静脉移植的羊膜间充质干细胞能够迁移到损伤区并对脊髓损伤有一定的修复作用。     

神经干细胞在体外诱导向胆碱能神经元定向分化后移植治疗脊髓损伤

目的 研究神经干细胞向胆碱能神经元定向分化后对脊髓横断损伤的修复作用.方法 采用GFP转基因孕鼠(E 12～14d)的海马分离、培养神经干细胞并诱导其向胆碱能神经元方向分化.SD成年大鼠以显微剪横断脊髓制成SCI模型.将SD大鼠18只分为3组:A组注入DMEM/F12培养液;B组注入神经于细胞的细胞液,C组注入在体外定向诱导为胆碱能神经元的细胞液;3组实验动物均于细胞移植后采用B B B评分法定期评估运动功能.于移植后第8周末,取出相应的脊髓阶段,行ChAT免疫组织化学染色,光镜观察.结果 从海马分离的细胞群具有自我更新能力,表达nestin,胎鼠骨骼肌提取液可以诱导这些细胞中的11.8%分化成为胆碱能神经元,与对照组差异明显.B组和C组所有大鼠BBB评分在移植细胞3周以后明显高于A组(P＜0.05),C组所有大鼠BBB评分在移植细胞4周以后明显高于B组(P＜0.05).在移植第8周末,冰冻切片中可见ChAT染色阳性细胞.结论 神经干细胞可以在体外诱导向胆碱能神经元定向分化,定向分化后移植应用在脊髓横断损伤治疗中,可明显改善运动功能.     

神经前体细胞移植治疗大鼠急性脊髓损伤的功能评价

目的：神经前体细胞移植治疗大鼠脊髓损伤的行为变化及功能评价。方法：采用改良A11en法建立大鼠脊髓损伤模型，术后9d，实验组脊髓损伤局部注射移植永生化神经前体细胞系G3。采用只注射培养液和不作治疗处理作为对照组。细胞移植后，采用BBB评分进行功能评价，每周评分1次，检测脊髓损伤大鼠后肢运动功能的改变。分别在细胞移植的第8周和第12周进行运动诱发电位的神经电生理检查，检测脊髓的传导功能。结果：实验组移植水生化神经前体细胞后，其BBB评分和对照组相比差异无显著性；但运动诱发电位与对照组相比明显提高。结论：永生化神经前体细胞移植可显著提高大鼠急性损伤脊髓的传导功能恢复。     

Functional recovery following traumatic spinal cord injury mediated by a unique polymer scaffold seeded with neural stem cells and Schwann cells

Background The most important objective of transplant studies in the injured spinal cord has been to provide a favorable environment for axonal growth. Moreover, the continuing discovery of new grafts is providing new potentially interesting transplant candidates. Our purpose was to observe the morphological and functional repair effects of the co-transplantation of neural stem cell （NSC）, Schwann ceils （SCs） and poly lactide-co-glycolide acid （PLGA） on the spinal cord injury of rats.Methods A scaffold of PLGA was fabricated. NSCs and SCs were cultured, with the NSCs labeled with 5-bromodeoxyuridine, and the complex of NSC/PLGA or NSC＋SCs/PLGA were constructed. Thirty-six Wistar rats were randomly divided into three groups： group A （transplantation of PLGA）, group B （transplantation of NSC/PLGA） and group C （transplantation of NSC＋SCs/PLGA）. The 3 mm length of the right hemicord was removed under the microscope in all rats. The PLGA or the complex of PLGA-celIs were implanted into the injury site. Basso-Beattie-Bresnahan （BBB）locomotion scores, motor and somatosensory evoked potential of lower limbs were examined to learn the rehabilitation of sensory and motor function at 4 weeks, 8 weeks, 12 weeks and 24 weeks after injury. All the recovered spinal cord injury （SCI） tissues were observed with HE staining, immunohistochemistry, and transelectronmicroscopy to identify the survival, migration and differentiation of the transplanted cells and the regeneration of neural fibres at 4 weeks, 8 weeks,12 weeks and 24 weeks after injury.Results （1） From 4 weeks to 24 weeks after injury, the BBB locomotion scores of cell-transplanted groups were better than those of the non-cell-transplanted group, especially group C （P 〈0.05）. The amplitudes of the somatosensory evoked potential （SEP） and motor-evoked potential （MEP） were improved after injury in groups B and C, but the amplitude of SEP and MEP at 4 weeks was lower than that at 12 weeks and 24 weeks after injury. Compared with group B, the amplitude of SEP and MEP in group C was improved. The amplitude of SEP and MEP was not improved after injury in group A. （2） HE staining revealed the volume of the scaffold decreased and the number of cells in the scaffold increased. Newly-grown capillaries also could be seen. Immunohistochemistry staining showed the transplanted NSCs could survive and migrate until 24 weeks and they could differentiate into neurons and oligodendrocytes. The regenerated axons were observed in the scaffold-cell complex with transelectronmicroscopy. The above manifestations were more extensive in group C.Conclusions The transplanted NSC can survive and migrate in the spinal cord of rats up to 24 weeks after injury, and they can differentiate into various neural cells. Co-transplantation of cells/PLGA can promote the functional recovery of the injured spinal cord. The effect of co-transplanting NSC＋SCs/PLGA is better than transplanting NSC/PLGA alone.     

人脐血干细胞移植促进大鼠脊髓损伤神经恢复

目的观察移植人脐血CD34 干细胞是否可以存活、分化、促进脊髓损伤的行为和功能恢复.方法26只Wister大鼠随机分成移植组和对照组.移植组行脊髓半切术并移植5-溴脱氧尿核苷(Brdu)标记的脐血CD34 细胞,对照组行脊髓半切术后注射PBS液.采用改良Tarlov评分标准对移植组和对照组所有大鼠在术前和术后24 h、1、2、3、4周进行运动功能评价.组织学和免疫组化分析移植细胞的定位和分化情况.结果移植后在脊髓病理切片中出现Brdu标记人脐血细胞,激光扫描共聚焦显微镜通过免疫荧光双标检测到7%Brdu阳性细胞表达神经胶质元纤维酸性蛋白(GFAP),2%Brdu阳性细胞表达神经元核抗原(NeuN).神经功能检测发现1周后移植组功能恢复较对照组具有显著性差异(P＜0.05).结论移植人脐血干细胞可以促进脊髓损伤的行为和功能恢复,为神经损伤治疗提供了有用的细胞源.     

应用超顺磁性氧化铁纳米粒子标记神经干细胞及活体磁共振示踪的实验研究

目的 探索超顺磁性氧化铁纳米粒子(SPIO)标记神经干细胞体的方法及其检测手段,研究标记细胞移植后在活体上磁共振信号的改变。方法 分离培养新生鼠皮层神经干细胞,使用SPIO和多聚赖氨酸联合标记神经干细胞;将标记后的神经干细胞移植入Wistar大鼠脑内,应用不同的扫描序列对脑内移植的神经干细胞进行示踪。结果 体外标记的神经干细胞普鲁士蓝染色见细胞浆内有许多蓝染的铁颗粒,电镜检查表明SPIO颗粒存在于标记细胞的吞饮小泡及细胞基质内,标记后的细胞可正常分化。脑内移植的标记细胞在磁共振上呈明显的低信号改变,以GREE序列信号改变最为明显。结论 超顺磁性氧化铁粒子可以用来标记神经干细胞,且对细胞增殖、分化无影响,SPIO颗粒存在于标记细胞的吞饮小泡及细胞基质内。标记后体内移植的神经干细胞可以在MR上产生明显的低信号改变。     

Experimental Study of Cell Migration and Functional Differentiation of Transplanted Neural Stem Cells Co-labeled with Superparamagnetic Iron Oxide and Brdu in an Ischemic Rat Model

Objective To explore the migration of transplanted neural stem cells co-labeled with superparamagnetic iron oxide （SPIO） and bromodeoxyuridine （Brdu） using the 4.7T MR system and to study the cell differentiation with immuno-histochemical method in ischemic rats. Methods Rat neural stem cells （NSCs） co-labelled with SPIO mediated by poly-L-lysine and bromodeoxyuridine （BrdU） were transplanted into the unaffected side of rat brain with middle cerebral artery occlusion （MCAO）. At weeks 1, 2, 3, 4, 5, and 6 after MCAO, migration of the labelled cells was monitored by MRI. At week 6 the rats were killed and their brain tissue was cut according to the migration site of transplanted ceils indicated by MRI and subjected to Prussian blue staining and immunohistochemical staining to observe the migration and differentiation of the transplanted NSCs. Results Three weeks after transplantation, the linear hypointensity area derived from the migration of labelled NSCs was observed by MRI in the corpus callosum adjacent to the injection site. Six weeks after the transplantation, the linear hypointensity area was moved toward the midline along the corpus callosum. MRI findings were confirmed by Prussian blue staining and immunohistochemical staining of the specimen at week 6 after the transplantation. Flourescence co-labelled immunohistochemical methods demonstrated that the transplanted NSCs could differentiate into astrocytes and neurons. Conclusion MRI can monitor the migration of SPIO-labelled NSCs after transplantation in a dynamical and non-invasive manner. NSCs transplanted into ischemic rats can differentiate into astrocytes and neurons during the process of migration.     

Human neural stem cells promote corticospinal axons regeneration and synapse reformation in injured spinal cord of rats

Background Axonal regeneration in lesioned mammalian central nervous system is abortive, and this causes permanent disabilities in individuals with spinal cord injuries. This paper studied the action of neural stem cell （NSC） in promoting corticospinal axons regeneration and synapse reformation in rats with injured spinal cord. Methods NSCs were isolated from the cortical tissue of spontaneous aborted human fetuses in accordance with the ethical request. The cells were discarded from the NSC culture to acquire NSC-conditioned medium. Sixty adult Wistar rats were randomly divided into four groups （n=15 in each）： NSC graft, NSC medium, graft control and medium control groups. Microsurgical transection of the spinal cord was performed in all the rats at the T11. The NSC graft group received stereotaxic injections of NSCs suspension into both the spinal cord stumps immediately after transection; graft control group received DMEM injection. In NSC medium group, NSC-conditioned medium was administered into the spinal cord every week; NSC culture medium was administered to the medium control group. Hindlimb motor function was assessed using the BBB Locomotor Rating Scale. Regeneration of biotin dextran amine （BDA） labeled corticospinal tract was assessed. Differentiation of NSCs and the expression of synaptophysin at the distal end of the injured spinal cord were observed under a confocal microscope. Group comparisons of behavioral data were analyzed with ANOVA. Results NSCs transplantation resulted in extensive growth of corticospinal axons and locomotor recovery in adult rats after complete spinal cord transection, the mean BBB scores reached 12.5 in NSC graft group and 2.5 in graft control group （P〈 0.05）. There was also significant difference in BBB score between the NSC medium （11.7） and medium control groups （3.7, P〈 0.05）. BDA traces regenerated fibers sprouted across the lesion site and entered the caudal part of the spinal cord. Synaptophysin expression colocalized with BDA positive axons and neurons distal to the injury site. Transplanted cells were found to migrate into the lesion, but not scatter along the route of axon grows. The cells differentiated into astrocytes or oligodendrocytes, but not into the neurons after transplantation. Furthermore, NSC medium administration did not limit the degree of axon sprouting and functional recovery of the injured rats compared to the NSC graft group. Conclusions Human embryonic neural stem cells can promote functional corticospinal axons regeneration and synapse reformation in the injured spinal cord of rats. The action is mainly through the nutritional effect of the stem cells on the spinal cord.     

BMSCs并BDNF移植治疗大鼠陈旧性脊髓损伤效果

目的探讨骨髓间充质干细胞(BMSCs)并脑源性神经营养因子(BDNF)移植治疗大鼠陈旧性脊髓损伤的效果。方法对48只Wistar大鼠采用改良的ALLEN撞击法建立脊髓损伤模型,将其随机分为4组,4周后4组分别注射BMSCs+BDNF、BMSCs、BDNF及DMEM干预。分别于移植后1、2、4周采用BBB评分评估大鼠后肢运动情况,并于移植后4周采用免疫组化法检测BMSCs在脊髓损伤部位的分布,及生长相关蛋白43(GAP-43)的表达。结果移植后4周,BMSCs+BDNF组及BMSCs组的BMSCs在脊髓损伤部位均得以存活。BMSCs+BDNF组与BMSCs组及BDNF组比较,脊髓空洞较少并且GAP-43阳性表达面积较高(F=35.57,q=4.97～25.84,P<0.05)。BMSCs+BDNF组BBB评分与其他组比较,差异有显著性(F=27.51,q=3.89～11.57,P<0.05)。结论 BMSCs+BDNF联合移植对于大鼠陈旧性脊髓损伤有较好的修复作用。     

Transplantation of human amniotic epithelial cells improves hindlimb function in rats with spinal cord injury

Background Human amniotic epithelial cells (HAECs), which have several characteristics similar to stem cells, therefore could possibly be used in cell therapy without creating legal or ethical problems. In this study, we transplanted HEACs into the injured spinal cord of rats to investigate if the cells can improve the rats’ hindlimb motor function. Methods HAECs were obtained from a piece of fresh amnion, labeled with Hoechst33342, and transplanted into the site of complete midthoracic spinal transections in adult rats. The rats (n=21) were randomly divided into three groups: Sham-operation group (n=7), cells-graft group (n=7), and PBS group (n=7). One rat of each group was killed for histological analysis at the second week after the transplantation. The other six rats of each group were killed for histological analysis after an 8-week behavioral testing. Hindlimb motor function was assessed by using the open-field BBB scoring system. Survival rate of the graft cells was observed at second and eighth weeks after the transplantation. We also detected the myelin sheath fibers around the lesions and the size of the axotomized red nucleus. A one-way ANOVA was used to compare the means among the groups. The significance level was set at P&lt;0.05.Results The graft HAECs survived for a long time (8 weeks) and integrated into the host spinal cord without immune rejection. Compared with the control group, HAECs can promote the regeneration and sprouting of the axons, improve the hindlimb motor function of the rats (BBB score: cells-graft group 9.0±0.89 vs PBS group 3.7±1.03, P&lt;0.01), and inhibit the atrophy of axotomized red nucleus [cells-graft group (526.47±148.42) &micro;m(2 )vs PBS group (473.69±164.73) &micro;m(2), P&lt;0.01]. Conclusion Transplantation of HAECs can improve the hindlimb motor function of rats with spinal cord injury.