Adenovirus-mediated human brain-derived neurotrophic factor gene-modified bone marrow mesenchymal stem cell transplantation for spinal cord injury

Rat bone marrow mesenchymal stem cells expressing brain-derived neurotrophic factor were successfully obtained using a gene transfection method,then intravenously transplanted into rats with spinal cord injury.At 1,3,and 5 weeks after transplantation,the expression of brain-derived neurotrophic factor and neurofilament-200 was upregulated in the injured spinal cord,spinal cord injury was alleviated,and Basso-Beattie-Bresnahan scores of hindlimb motor function were significantly increased.This evidence suggested that intravenous transplantation of adenovirus-mediated brain-derived neurotrophic factor gene-modified rat bone marrow mesenchymal stem cells could play a dual role,simultaneously providing neural stem cells and neurotrophic factors.     

Electrophysiological functional recovery in a rat model of spinal cord hemisection injury following bone marrow-derived mesenchymal stem cell transplantation under hypothermia

Following successful establishment of a rat model of spinal cord hemisection injury by resecting right spinal cord tissues, bone marrow stem cells were transplanted into the spinal cord lesions via the caudal vein while maintaining rectal temperature at 34 ± 0.5°C for 6 hours (mild hypothermia). Hematoxylin-eosin staining showed that astrocytes gathered around the injury site and formed scars at 4 weeks post-transplantation. Compared with rats transplanted with bone marrow stem cells under normal temperature, rats transplanted with bone marrow stem cells under hypothermia showed increased numbers of proliferating cells (bromodeoxyuridine-positive cells), better recovery of somatosensory-evoked and motor-evoked potentials, greater Basso, Beattie, and Bresnahan locomotor rating scores, and an increased degree of angle in the incline plate test. These findings suggested that hypothermia combined with bone marrow mesenchymal stem cells transplantation effectively promoted electrical conduction and nerve functional repair in a rat model of spinal cord hemisection injury.     

Cell transplantation for the treatment of spinal cord injury–bone marrow stromal cells and choroid plexus epithelial cells

Transplantation of bone marrow stromal cells(BMSCs) enhanced the outgrowth of regenerating axons and promoted locomotor improvements of rats with spinal cord injury(SCI).BMSCs did not survive long-term,disappearing from the spinal cord within 2–3 weeks after transplantation.Astrocyte-devoid areas,in which no astrocytes or oligodendrocytes were found,formed at the epicenter of the lesion.It was remarkable that numerous regenerating axons extended through such astrocyte-devoid areas.Regenerating axons were associated with Schwann cells embedded in extracellular matrices.Transplantation of choroid plexus epithelial cells(CPECs) also enhanced axonal regeneration and locomotor improvements in rats with SCI.Although CPECs disappeared from the spinal cord shortly after transplantation,an extensive outgrowth of regenerating axons occurred through astrocyte-devoid areas,as in the case of BMSC transplantation.These findings suggest that BMSCs and CPECs secret neurotrophic factors that promote tissue repair of the spinal cord,including axonal regeneration and reduced cavity formation.This means that transplantation of BMSCs and CPECs promotes "intrinsic" ability of the spinal cord to regenerate.The treatment to stimulate the intrinsic regeneration ability of the spinal cord is the safest method of clinical application for SCI.It should be emphasized that the generally anticipated long-term survival,proliferation and differentiation of transplanted cells are not necessarily desirable from the clinical point of view of safety.     

Effect of intravenous transplantation of bone marrow mesenchymal stem cells on neurotransmitters and synapsins in rats with spinal cord injury

Bone marrow mesenchymal stem cells were isolated, purified and cultured in vitro by Percoll density gradient centrifugation combined with the cell adherence method. Passages 3-5 bone marrow mesenchymal stem cells were transplanted into rats with traumatic spinal cord injury via the caudal vein. Basso-Beattie-Bresnahan scores indicate that neurological function of experimental rats was significantly improved over transplantation time (1-5 weeks). Expressions of choline acetyltransferase, glutamic acid decarboxylase and synapsins in the damaged spinal cord of rats was significantly increased after transplantation, determined by immunofluorescence staining and laser confocal scanning microscopy. Bone marrow mesenchymal stem cells that had migrated into the damaged area of rats in the experimental group began to express choline acetyltransferase, glutamic acid decarboxylase and synapsins, 3 weeks after transplantation. The Basso-Beattie- Bresnahan scores positively correlated with expression of choline acetyltransferase and synapsins. Experimental findings indicate that intravenously transplanted bone marrow mesenchymal stem cells traverse into the damaged spinal cord of rats, promote expression of choline acetyltransferase, glutamic acid decarboxylase and synapsins, and improve nerve function in rats with spinal cord injury.     

visual bone marrow mesenchymal stem cell transplantation in the repair of spinal cord injury

An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord injury by dropping a weight onto the spinal cord at T7–8. Superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells were transplanted into the injured spinal cord via the subarachnoid space. An outer magnetic field was used to successfully guide the labeled cells to the lesion site. Prussian blue staining showed that more bone marrow mesenchymal stem cells reached the lesion site in these rats than in those without magnetic guidance or superparamagnetic iron oxide labeling, and immunofluorescence revealed a greater number of complete axons at the lesion site. Moreover, the Basso, Beattie and Bresnahan(BBB) locomotor rating scale scores were the highest in rats with superparamagnetic labeling and magnetic guidance. Our data confirm that superparamagnetic iron oxide nanoparticles effectively label bone marrow mesenchymal stem cells and impart sufficient magnetism to respond to the external magnetic field guides. More importantly, superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells can be dynamically and non-invasively tracked in vivo using magnetic resonance imaging. Superparamagnetic iron oxide labeling of bone marrow mesenchymal stem cells coupled with magnetic guidance offers a promising avenue for the clinical treatment of spinal cord injury.     

Transplantation of Nogo-66 receptor gene-silenced cells in a poly(D,L-lactic-co-glycolic acid) scaffold for the treatment of spinal cord injury

Inhibition of neurite growth,which is in large part mediated by the Nogo-66 receptor,affects neural regeneration following bone marrow mesenchymal stem cell transplantation.The tissue engineering scaffold poly(D,L-lactide-co-glycolic acid) has good histocompatibility and can promote the growth of regenerating nerve fibers.The present study used small interfering RNA to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells and Schwann cells,which were subsequently transplanted with poly(D,L-lactide-co-glycolic acid) into the spinal cord lesion regions in rats.Simultaneously,rats treated with scaffold only were taken as the control group.Hematoxylin-eosin staining and immunohistochemistry revealed that at 4 weeks after transplantation,rats had good motor function of the hind limb after treatment with Nogo-66 receptor gene-silenced cells plus the poly(D,L-lactide-co-glycolic acid) scaffold compared with rats treated with scaffold only,and the number of bone marrow mesenchymal stem cells and neuron-like cells was also increased.At 8 weeks after transplantation,horseradish peroxidase tracing and transmission electron microscopy showed a large number of unmyelinated and myelinated nerve fibers,as well as intact regenerating axonal myelin sheath following spinal cord hemisection injury.These experimental findings indicate that transplantation of Nogo-66 receptor gene-silenced bone marrow mesenchymal stem cells and Schwann cells plus a poly(D,L-lactide-co-glycolic acid) scaffold can significantly enhance axonal regeneration of spinal cord neurons and improve motor function of the extremities in rats following spinal cord injury.     

Bone marrow mesenchymal stem cells repair spinal cord ischemia/reperfusion injury by promoting axonal growth and anti-autophagy

Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after trans- plantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are known to protect against spinal cord ischemia/reperfusion injury through anti-apoptotic effects, the precise mechanisms remain unclear. In the present study, bone marrow mesenchymal stem cells were cultured and proliferated, then transplanted into rats with ischemia/reperfusion injury via retro-orbital injection. Immunohistochemistry and immunofluorescence with subsequent quantification revealed that the expression of the axonal regeneration marker, growth associated protein-43, and the neuronal marker, microtubule-as- sociated protein 2, significantly increased in rats with bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Fur- thermore, the expression of the autophagy marker, microtubule-associated protein light chain 3B, and Beclin 1, was significantly reduced in rats with the bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Western blot analysis showed that the expression of growth associated protein-43 and neuro- filament-H increased but light chain 3B and Beclin 1 decreased in rats with the bone marrow mesenchymal stem cell transplantation. Our results therefore suggest that bone marrow mes- enchymal stem cell transplantation promotes neurite growth and regeneration and prevents autophagy. These responses may likely be mechanisms underlying the protective effect of bone marrow mesenchymal stem cells against spinal cord ischemia/reperfusion injury.     

骨髓间充质干细胞移植治疗脊髓损伤的MRI活体示踪

Non-invasive tracing in vivo can be used to observe the migration and distribution of grafted stem cells,and can provide experimental evidence for treatment.This study utilized adenovirus-carrying enhanced green fluorescent protein(AD5/F35-eGFP) and superparamagnetic iron oxide(SPIO)-labeled bone marrow mesenchymal stem cells(BMSCs).BMSCs,double-labeled by AD5/F35-eGFP and SPIO,were transplanted into rats with spinal cord injury via the subarachnoid space.MRI tracing results demonstrated that BMSCs migrated to the injured spinal cord over time(T2 hypointensity signals).This result was verified by immunofluorescence.These results indicate that MRI can be utilized to trace in vivo the SPIO-labeled BMSCs after grafting.     

Human bone marrow mesenchymal stem cell transplantation attenuates axonal injury in stroke rats

Previous studies have shown that transplantation of human bone marrow mesenchymal stem cells promotes neural functional recovery after stroke, but the neurorestorative mechanisms remain largely unknown. We hypothesized that functional recovery of myelinated axons may be one of underlying mechanisms. In this study, an ischemia/reperfusion rat model was established using the middle cerebral artery occlusion method. Rats were used to test the hypothesis that intravenous transplantation of human bone marrow mesenchyrnal stem cells through the femoral vein could exert neuroprotective effects against cerebral ischemia via a mechanism associated with the ability to attenuate axonal injury. The results of behavioral tests, infarction volume analysis and immunohistochemistry showed that cerebral ischemia caused severe damage to the myelin sheath and axons. After rats were intravenously transplanted with human bone marrow mesenchymal stem cells, the levels of axon and myelin sheath-related proteins, including microtubule-associated protein 2, myelin basic protein, and growth-associated protein 43, were elevated, infarct volume was decreased and neural function was improved in cerebral ischemic rats. These findings suggest that intravenously transplanted human bone marrow mesenchymal stem cells promote neural function. Possible mechanisms underlying these beneficial effects include resistance to demyelination after cerebral ischemia, prevention of axonal degeneration, and promotion of axonal regeneration.     

局部注射骨髓间充质干细胞治疗大鼠脊髓损伤：运动功能有改善吗？

背景：目前研究多为骨髓间充质干细胞的体外培养及细胞移植对颅内疾病的治疗,对植入细胞在损伤脊髓中的成活、分化、迁移、结构重建等了解有限。 目的：探讨局部骨髓间充质干细胞移植在脊髓损伤修复中的作用和骨髓间充质干细胞替代治疗的可行性。 方法：成年健康雌性SD大鼠随机分为细胞移植组和对照组,建立SD大鼠脊髓横断损伤模型,伤后即刻分别向损伤区局部移植大鼠骨髓间充质干细胞悬液或无钙镁磷酸缓冲液。在术前和术后1 d,1周,2周,3周,4周和8周进行BBB评分,观测大鼠的运动功能,并于移植后1周免疫组织化学染色法观察BrdU标记的骨髓间充质干细胞在脊髓损伤处的存活情况,移植后4周进行损伤脊髓的大体观察和组织学检测。 结果与结论：移植后第1~8周细胞移植组BBB评分均髙于对照组;术后1周免疫组织化学染色结果显示在细胞移植组大鼠脊髓远端检测到BrdU阳性细胞,术后4周脊髓损伤处发现有神经纤维。证实通过损伤后立即局部注射的方式将骨髓间充质干细胞移植进大鼠脊髓损伤区,细胞可在损伤区存活;存活的骨髓间充质干细胞可分化为神经元,在损伤局部形成神经元通路,从而促进脊髓神经纤维传导功能的恢复,并促进高位脊髓损伤后大鼠后肢运动功能恢复。     

骨髓间充质干细胞立体定向移植治疗大鼠脊髓损伤*

摘要 背景：传统观念认为,神经组织损伤后几乎不能再生,以往对SCI的治疗缺乏有效手段,致使本病致残率高,疗效差。干细胞治疗关键在于移植具有再生能力的干细胞,通过多种作用机制,可以重建中枢神经系统的结构和功能,近年来引起了广泛的关注。 目的：探讨立体定向移植骨髓间充质干细胞（MSCs）对大鼠脊髓损伤修复的影响并探讨其机制 设计、时间及地点：随机对照动物实验,于2007-10/2008-6在天津市环湖医院完成。 材料：1月龄SD大鼠20只,用于制备骨髓间充质干细胞;健康成年Wistar大鼠45只,雌性、同系,体质量280±20 g。将动物随机分为对照组、假手术组与移植组,每组各15只。 方法：密度梯度离心法结合贴壁筛选法分离骨髓间充质干细胞,经流式细胞仪鉴定为MSCs。以动脉瘤夹夹闭法制备大鼠脊髓损伤（SCI）模型,在SCI大鼠致伤后第7天,通过立体定向途径移植MSCs到移植组大鼠脊髓损伤中心,移植等量生理盐水至假手术组大鼠脊髓损伤中心,对照组大鼠不做处理。 主要观察指标：SCI大鼠损伤前及损伤后第7天、14天、30天、60天、90天的BBB评分;损伤后第90天处死大鼠,观察其脊髓组织中有无BrdU阳性细胞、Brdu+NSE、Brdu+GFAP、Brdu+bFGF、Brdu+BDNF免疫组化双染阳性细胞并观察NSE、GFAP、bFGF、BDNF单染阳性细胞。 结果： ①BBB评分发现,MSCs移植组大鼠BBB后肢功能评分恢复优于对照组（p<0.05）;假手术组BBB评分在损伤后30天内恢复速度慢于对照组（p<0.05）,至第90天与对照组比较无显著差异（P>0.05）;②免疫组织化学染色发现,移植组大鼠脊髓内在损伤中心及头、尾端距离脊髓损伤中心1cm处均可见BrdU染色阳性细胞及Brdu+NSE、Brdu+GFAP、Brdu+bFGF、Brdu+BDNF免疫组化双染阳性细胞。移植组NSE、GFAP、bFGF、BDNF单染阳性细胞数明显高于对照组和假手术组（p<0.05）。 结论： MSCs移植可以促进SCI大鼠的神经功能的恢复,其机制可能与移植细胞分化为神经元样和神经胶质细胞样细胞,并分泌或促进宿主分泌神经营养因子有关。 关键词 脊髓损伤 骨髓间充质干细胞 立体定向 细胞移植     

大鼠骨髓间充质干细胞静脉移植对脊髓损伤的修复作用

目的初步探讨骨髓间充质干细胞（BMSCs）静脉移植对脊髓损伤后神经功能恢复和神经修复的影响。方法体外培养BMSCs，改良Allen法制备大鼠脊髓损伤模型，经尾静脉移植Brdu标记的BMSCs，损伤后24h、移植后1、3、5周评价实验动物的神经功能状况，并检测BMSCs在体内迁移、存活以及分化情况，电子显微镜观察组织形态学变化。结果移植的BMSCs在宿主损伤脊髓中聚集并存活，3～5周后有部分移植细胞表达神经元特异性烯醇化酶（NSE）、神经丝蛋白（NF）、微管相关蛋白（MAP2）；BMSCs静脉移植组大鼠运动功能改善，BBB评分高于对照组（P〈0．05）；5周后组织学观察，与对照组相比移植组损伤区脊髓结构较完整。结论BMSCs经静脉移植后可向脊髓损伤处聚集并存活分化，促进神经修复及神经功能的恢复。     

PKH67示踪骨髓间充质干细胞迁移至损伤脊髓的实验研究

目的 探讨SCI后体外移植PKH67标记的BMSCs迁移至脊髓损伤处并进行增值和分化的动员情况。方法 用梯度离心法分离和培养出SD 大鼠第3代BMSCs,用绿色荧光染料PKH67标记; 采用钳夹法制备脊髓损伤(SCI)模型,分为实验组(n=15)、对照组(n=16)、假手术组(n=16); SCI术后对脊髓损伤组织进行HE染色,实验组和假手术组于术后尾静脉移植含有1×10⁷个BMSCs的0.5 mL生理盐水,对照组注射等量生理盐水; 分别于术后1、7、14、21 d观察大鼠后肢运动功能恢复情况,并做BBB分; 术后21 d后取脊髓组织,行免疫荧光染色,观察BMSCs的迁移,增值和分化情况。结果(1)镜下可见损伤脊髓形成的空洞、坏死及炎性细胞的增多;(2)共聚焦荧光显微镜观察显示术后21 d实验组脊髓损伤部位可见移植的BMSCs, 部分BMSCs呈GFAP和Nestin阳性表达; 假手术组无 PKH67标记的BMSCs; 实验组GFAP和Nestin阳性细胞数较对照组和假手术组明显增加(P<0.05),对照组较假手术组增加不明显(P>0.05);(3)实验组和对照组BBB评分均有增加,但实验组BBB评分显著高于对照组(P<0.05)。结论 PKH67示踪的BMSCs可迁移至损伤脊髓部位,进行增值并分化为神经元样细胞,促进损伤脊髓的神经功能恢复。     

骨髓间充质干细胞不同移植途径治疗大鼠脊髓损伤的比较

背景：在适当的生长环境下，中枢神经系统内的一些受损的神经元轴突有少许再生，并能与靶细胞形成功能性的突触联系。 目的：比较局部注射和尾静脉注射途径移植骨髓间充质干细胞对大鼠脊髓损伤神经功能恢复的作用。 设计、时间及地点：细胞组织学对照观察，于2007-03/2008-04在承德医学院完成。 材料：健康成年雄性SD大鼠40只，由解放军军事医学科学院动物中心（北京）提供。 方法：取4只大鼠，采用密度梯度离心法和贴壁法体外分离培养骨髓间充质干细胞，传至第2代于临用前24 h行BrdU标记。余36只大鼠均建立T12脊髓损伤模型，1周后随机分为3组，局部注射组于损伤部位上下位点注射1×106个骨髓间充质干细胞至损伤大鼠体内；尾静脉注射组通过尾静脉移植等量骨髓间充质干细胞至损伤大鼠体内；模型对照组不行细胞移植。 主要观察指标：神经功能缺损BBB评分，苏木精-伊红染色病理学检测，细胞分化免疫组化染色结果。 结果：细胞移植后2，4，6周，模型对照组神经功能缺损BBB评分均显著低于局部注射组、尾静脉注射组（F=721.373，F=1 114.450，F=1 004.099，P均 < 0.01）；局部注射组神经功能缺损BBB评分均显著高于尾静脉注射组（t=55.261，t=71.385，t=78.135，P均 < 0.01）。苏木精-伊红染色结果显示，模型对照组损伤脊髓组织有较多空腔，横断处形成大量空泡；局部注射组无明显空腔，空泡小而少，间质水肿较轻。移植后4，6周，部分植入的骨髓间充质干细胞呈微管相关蛋白2及胶质纤维酸性蛋白双阳性表达。 结论：局部注射和尾静脉注射两种途径移植的骨髓间充质干细胞均可在脊髓损伤处存活、分化并改善神经功能，且局部注射的效果优于尾静脉注射。     

胎鼠神经干细胞局部注射移植大鼠高位脊髓损伤缺损处：体感及运动诱发电位与后肢运动功能评价

背景：如何促进脊髓损伤后的神经再生和功能恢复始终是医学界一大难题,胚胎神经干细胞有利于神经元的存活,并能促进轴突再生。 目的：观察胚胎鼠神经干细胞局部注射移植治疗高位脊髓损伤大鼠的可行性,以神经电生理及后肢运动功能评分评价其效果。 设计、时间及地点：细胞学体内实验,于2007-06/2008-06在哈尔滨医科大学动物实验中心完成。 材料：健康成年雌性SD大鼠40只,随机分为生理盐水组、细胞移植组,20只/组。另取孕14 d的SD大鼠5只用于制备胚胎神经干细胞。 方法：生理盐水组、细胞移植组大鼠均建立高位脊髓损伤模型,取双侧第8~10对肋间神经各2 cm,交叉植入脊髓缺损处(近端白质与远端灰质、远端白质与近端灰质),细胞移植组局部注射鼠胚胎神经干细胞2×106个,生理盐水组局部注射等量无菌生理盐水。 主要观察指标：通过体感诱发电位和运动诱发电位的检测,观察神经电生理恢复情况;通过BDA顺行神经示踪,观察运动传导束恢复情况;BBB后肢运动功能评分结果。 结果：细胞移植组大鼠体感诱发电位及运动诱发电位的潜伏期、波幅明显优于生理盐水组(P < 0.01);细胞移植组大鼠在损伤区有较多BDA标记阳性神经纤维通过,而生理盐水组未见BDA标记阳性神经纤维;细胞移植组大鼠BBB后肢运动功能评分较生理盐水组明显提高(P < 0.01)。 结论：胎鼠神经干细胞局部注射可以较好地恢复高位脊髓损伤后的神经电生理及后肢运动功能。     

电针联合骨髓基质细胞移植对脊髓损伤大鼠神经功能恢复的影响

背景：研究认为骨髓基质细胞在损伤、缺血的脑脊髓组织中定向神经分化与损伤局部的微环境变化有关,特别是神经营养因子的诱导作用。课题组前期实验已证实,针刺可以通过增加各种细胞因子及营养因子的表达,促进神经的再生及修复。 目的：观察电针联合骨髓基质细胞移植对脊髓损伤大鼠神经功能恢复的影响。 设计、时间及地点：随机对照动物实验,于2005-03/2006-07在哈尔滨医科大学细胞生物实验室完成。 材料：健康纯系SD大鼠80只,取8只用于骨髓基质细胞的分离培养,剩余72只随机分为4组：空白对照组、细胞移植组、电针组、联合组,18只/组。KWD-808II型脉冲电针仪由江苏武进第三无线电厂生产。 方法：取体外分离培养的第3代骨髓基质细胞,移植前72 h行BrdU标记,调整细胞浓度为1×1011 L-1备用。4组大鼠均建立脊髓损伤模型,造模后细胞移植组将骨髓基质细胞悬液缓慢注入到脊髓损伤临近区域的灰白质交界处,总细胞数6×105个;空白对照组同法注射等量磷酸盐缓冲液;电针组于造模成功后24 h采用脉冲电针仪进行夹脊电针治疗,在距损伤处上下端两个椎体的棘突间隙旁开距中线3.0~4.0 mm处取穴,针刺20 min,1次/d;联合组行骨髓基质细胞移植+夹脊电针治疗。 主要观察指标：移植后 3,7,14 d,应用联合行为评分评估大鼠脊髓损伤后神经功能的改善状况;免疫双标法检测BrdU标记的骨髓基质细胞胶质纤维酸性蛋白、神经元烯醇化酶的表达。 结果：损伤后3,7,14 d与空白对照组比较,细胞移植组、电针组、联合组联合行为评分均有显著性差异(P < 0.05,0.05,0.01);联合组神经功能恢复情况明显优于细胞移植组、电针组(P < 0.05);而细胞移植组、电针组之间比较无明显差异(P > 0.05)。与空白对照组相比,细胞移植组、电针组损伤区脊髓结构相对较完整,联合组脊髓结构更加完整,骨髓基质细胞移植的组织内可见 BrdU标记细胞在损伤区及其周边区明显聚集并存活;移植后14 d细胞移植组神经元烯醇化酶和胶质纤维酸性蛋白阳性细胞率分别分7.2%和1.5%,联合组阳性细胞率分别为7.9%和2.1%。 结论：骨髓基质细胞移植后可在宿主体内存活,电针可以促进骨髓基质细胞向神经细胞的分化,电针与骨髓基质细胞移植联合应用可以明显改善脊髓损伤大鼠的运动及感觉功能。     

Functional recovery and microenvironmental alterations in a rat model of spinal cord injury following human umbilical cord blood-derived mesenchymal stem cells transplantation

BACKGROUND: Transplantation of human umbilical cord blood-derived mesenchymal stem cells (MSCs) has been shown to benefit spinal cord injury (SCI) repair. However, mechanisms of microenvironmental regulation during differentiation of transplanted MSCs remain poorly understood. OBJECTIVE: To observe changes in nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and interleukin-8 (IL-8) expression following transplantation of human umbilical cord-derived MSCs, and to explore the association between microenvironment and neural functional recovery following MSCs transplantation.DESIGN, TIME AND SETTING: A randomized, controlled, animal experiment was performed at the Department of Orthopedics, First Affiliated Hospital of Soochow University from April 2005 to March 2007. MATERIALS: Human cord blood samples were provided by the Department of Gynecology and Obstetrics, First Affiliated Hospital of Soochow University. Written informed consent was obtained. METHODS: A total of 62 Wister rats were randomly assigned to control (n = 18), model (n = 22, SCI + PBS), and transplantation (n = 22, SCI + MSCs) groups. The rat SCI model was established using the weight compression method. MSCs were isolated from human umbilical cord blood and cultured in vitro for several passages. 5-bromodeoxyuridine (BrdU)-labeled MSCs (24 hours before injection) were intravascularly transplanted. MAIN OUTCOME MEASURES: The rats were evaluated using the Basso, Beattie and Bresnahan (BBB) locomotor score and inclined plane tests. Transplanted cells were analyzed following immunohistochemistry. Enzyme-linked immunosorbant assay was performed to determine NGF, BDNF, and IL-8 levels prior to and after cell transplantation.RESULTS: A large number of BrdU-positive MSCs were observed in the SCI region of the transplantation group, and MSCs were evenly distributed in injured spinal cord tissue 1 week after transplantation. BBB score and inclined plane test results revealed significant functional improvement in the transplantation group compared to the model group (P< 0.05), which was maintained for 2-3 weeks. Compared to the model group, NGF and BDNF levels were significantly increased in the injured region following MSCs transplantation at 3 weeks (P < 0.05), but IL-8 levels remained unchanged (P > 0.05).CONCLUSION: MSCs transplantation increased NGF and BDNF expression in injured spinal cord tissue. MSCs could promote neurological function recovery in SCI rats by upregulating NGF expression and improving regional microenvironments.     

Bone marrow mesenchymal stem cells stimulated with low‐intensity pulsed ultrasound: Better choice of transplantation treatment for spinal cord injury

Stem cell transplantation, especially treatment with bone marrow mesenchymal stem cells (BMSCs), has been considered a promising therapy for the locomotor and neurological recovery of spinal cord injury (SCI) patients. However, the clinical benefits of BMSCs transplantation remain limited because of the considerably low viability and inhibitory microenvironment. In our research, low‐intensity pulsed ultrasound (LIPUS), which has been widely applied to clinical applications and fundamental research, was employed to improve the properties of BMSCs. The most suitable intensity of LIPUS stimulation was determined. Furthermore, the optimized BMSCs were transplanted into the epicenter of injured spinal cord in rats, which were randomized into four groups: (a) Sham group (n = 10), rats received laminectomy only and the spinal cord remained intact. (b) Injury group (n = 10), rats with contused spinal cord subjected to the microinjection of PBS solution. (c) BMSCs transplantation group (n = 10), rats with contused spinal cord were injected with BMSCs without any priming. (d) LIPUS‐BMSCs transplantation group (n = 10), BMSCs stimulated with LIPUS were injected at the injured epicenter after contusion. Rats were then subjected to behavioral tests, immunohistochemistry, and histological observation. It was found that BMSCs stimulated with LIPUS obtained higher cell viability, migration, and neurotrophic factors expression in vitro. The rate of apoptosis remained constant. After transplantation of BMSCs and LIPUS‐BMSCs postinjury, locomotor function was significantly improved in LIPUS‐BMSCs transplantation group with higher level of brain‐derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the epicenter, and the expression of neurotrophic receptor was also enhanced. Histological observation demonstrated reduced cavity formation in LIPUS‐BMSCs transplantation group when comparing with other groups. The results suggested LIPUS can improve BMSCs viability and neurotrophic factors expression in vitro, and transplantation of LIPUS‐BMSCs could promote better functional recovery, indicating possible clinical application for the treatment of SCI.