HRP逆行示踪评价复合骨髓间充质干细胞的无细胞神经移植物

背景：作者前期将无细胞神经移植物与骨髓间充质干细胞复合培养,成功构建了组织工程人工神经。 目的：应用辣根过氧化物酶(HRP)神经逆行示踪技术对无细胞神经移植物复合骨髓间充质干细胞构建的神经移植复合体桥接大鼠坐骨神经缺损后运动神经元的保护作用进行评价。 方法：成年清洁级健康雄性SD大鼠,随机分成3组：①实验组：采用复合骨髓间充质干细胞的无细胞神经移植物桥接大鼠坐骨神经缺损。②空白对照组：采用无细胞神经移植物桥接大鼠坐骨神经缺损。③自体神经对照组：采用自体神经移植桥接大鼠坐骨神经缺损。术后12周应用辣根过氧化物酶神经逆行示踪技术对脊髓前角运动神经元的再生进行评价。 结果与结论：术后12周脊髓前角运动神经元再生评价结果显示：实验组优于无细胞神经移植物组,而与自体神经移植物组相比差异无显著性意义。证实无细胞神经移植物复合骨髓间充质干细胞构建组织工程人工神经修复大鼠坐骨神经缺损,对大鼠脊髓运动神经元具有保护作用,可能达到与自体神经移植相似的效果。 关键词：无细胞神经移植物;骨髓间充质干细胞;辣根过氧化物酶;神经移植;大鼠     

大鼠脂肪和骨髓来源间充质干细胞的生物学特性比较

背景：除骨髓外,人们已从胎盘组织、脐带血肌肉组织、脂肪组织中分离到了间充质干细胞。 目的：比较大鼠脂肪和骨髓间充质干细胞生物学特性和免疫调节功能的差异。 方法：脂肪间充质干细胞和骨髓间充质干细胞分别来自BN大鼠的脂肪和骨髓。体外分离、纯化脂肪和骨髓来源间充质干细胞,进行细胞形态、表面标志、生长动力学、分化潜能鉴定;混合淋巴细胞反应比较两种细胞的免疫调节特性。 结果与结论：脂肪间充质干细胞与骨髓间充质干细胞光镜和透射电镜下形态相似,第3代的脂肪间充质干细胞和骨髓间充质干细胞均高表达CD29,CD90,低表达CD34,CD45,CD11b;第3,4,5代脂肪间充质干细胞增殖速度明显快于骨髓间充质干细胞;两者都具有低免疫原性,可以抑制异基因抗原引起的T淋巴细胞增殖,且这种抑制作用与细胞数目成正相关,等量脂肪间充质干细胞和骨髓间充质干细胞抑制作用差异无显著性意义。结果证实脂肪间充质干细胞具有和骨髓间充质干细胞同样的低免疫原性和免疫调节功能。     

Transplantation of mesenchymal stem cells from human umbilical cord versus human umbilical cord blood for peripheral nerve regeneration

BACKGROUND: Mesenchymal stem cells (MSCs) appear to be a good alternative to Schwann cells in the treatment of peripheral nerve injury. Fetal stem cells, like umbilical cord blood (UCB) and umbilical cord (UC) stem cells, have several advantages over adult stem cells.OBJECTIVE: To assess the effects of UC-derived MSCs (UCMSCs) and UCB-derived MSCs (UCBMSCs) in repair of sciatic nerve defects. DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed at the laboratory of Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, from July to December 2009. MATERIALS: UCMSCs were provided by the Research Institute of Biotechnology, Dongguk University. UCBMSCs were provided by the Laboratory of Stem Cells and Tumor Biology, College of Veterinary Medicine, Seoul National University. Dulbecco's modified Eagle's medium (DMEM) was purchased from Gibco-BRL, USA. METHODS: Seven-week-old Sprague-Dawley rats were randomly and evenly divided into three groups: DMEM, UCBMSCs, and UCMSCs. A 10-mm defect in the left sciatic nerve was constructed in all rats. DMEM (15 μL) containing 1 × 106 UCBMSCs or UCMSCs was injected into the gap between nerve stumps, with the surrounding epineurium as a natural conduit. For the DMEM group, simple DMEM was injected. MAIN OUTCOME MEASURES: At 7 weeks after sciatic nerve dissection, dorsal root ganglia neurons were labeled by fluorogold retrograde labeling. At 8 weeks, electrophysiology and histomorphometry were performed. At 2, 4, 6, and 8 weeks after surgery, sciatic nerve function was evaluated using gait analysis.RESULTS: The UCBMSCs group and the UCMSCs group exhibited similar sciatic nerve function and electrophysiological indices, which were better than the DMEM group, as measured by gait analysis (P < 0.05). Fluorogold retrograde labeling of sciatic nerve revealed that the UCBMSCs group demonstrated a higher number of labeled neurons; however, the differences were not significant. Histomorphometric indices were similar in the UCBMSCs and UCMSCs groups, and total axon counts, particularly axon density (P < 0.05), were significantly greater in the UCBMSCs and UCMSCs groups than in the DMEM group. CONCLUSION: Transplanting either UCBMSCs or UCMSCs into axotomized sciatic nerves could accelerate and promote sciatic nerve regeneration over 8 weeks. Both treatments had similar effects on nerve regeneration.     

小胶质细胞活化刺激骨髓间充质干细胞释放胶质细胞源性神经营养因子保护多巴胺能神经元的实验☆

背景：目前尚未见骨髓间充质干细胞对活化的小胶质细胞特异性反应的报道，且有关骨髓间充质干细胞在特定微环境下如何维持多巴胺能神经元的存活也缺乏相应的实验证据。 目的：观察骨髓间充质干细胞在活化的小胶质细胞刺激下保护多巴胺能神经元存活的作用。 方法：取Wistar大鼠，贴壁法分离培养骨髓间充质干细胞，体外培养并活化小胶质细胞，酶消化法培养中脑多巴胺能神经元。实验分为5组：骨髓间充质干细胞组；小胶质细胞组；脂多糖+小胶质细胞组；骨髓间充质干细胞+脂多糖+小胶质细胞组；分别取各实验组的培养上清，对中脑多巴胺神经元进行培养。单纯多巴胺能神经元组采用体积分数为10%胎牛血清+DMEM/F12进行培养。采用免疫荧光技术检测不同微环境对多巴胺能神经元存活的影响及不同微环境对骨髓间充质干细胞释放胶质细胞源性神经营养因子的影响。 结果与结论：含有骨髓间充质干细胞的实验组胶质细胞源性神经营养因子的释放量均较相应的对照组高。酪氨酸羟化酶免疫荧光染色结果发现，单纯多巴胺能神经元组神经元的存活率为15%；小胶质细胞组多巴胺能神经元的存活率为10%；骨髓间充质干细胞组多巴胺能神经元的存活率为35%；脂多糖+小胶质细胞组多巴胺能神经元的存活率为5%；而骨髓间充质干细胞+脂多糖+小胶质细胞组多巴胺能神经元的存活率达到了28%，高于除骨髓间充质干细胞组外的其他各组(P < 0.05)。此外体外培养多巴胺能神经元存活率随培养时间延长下降，但含有骨髓间充质干细胞实验组的多巴胺能神经元存活率明显高于相应对照组。提示小胶质细胞活化刺激骨髓间充质干细胞上调胶质细胞源性神经营养因子表达，使得多巴胺能神经元免受毒素的损害，抑制了多巴胺能神经元的延迟性死亡。     

Bone marrow cells are able to increase vessels number during repair of sciatic nerve lesion

The aim of this study was to compare the outcomes of nerve autografts (GRF) and venous grafts containing mononuclear bone marrow cells (BMCs) in sciatic nerve-lesioned rats. Control animals underwent sham operations (SHAM), received empty venous grafts (EPV), or received venous grafts containing BMC vehicle (AGR). Outcome was evaluated through sciatic functional index (SFI), morphometric and morphologic analyses of the nerve distal to the lesion, and the number of spinal cord motor neurons positive for the retrograde tracer, Fluoro-Gold. All groups exhibited poor results in SFI when compared to SHAM animals throughout the postoperative period. All groups also had a significantly greater fiber density, decreased fiber diameter, and decreased motor neuron number than the SHAM group. No significant difference between the GRF and BMC groups was observed in any of these parameters. On the other hand, vessel density was significantly higher in BMC than all other groups. BMC-containing venous grafts are superior to nerve autografts in increasing vessel density during sciatic nerve regeneration.     

Differentiation of mesenchymal stem cells to support peripheral nerve regeneration in a rat model

Mesenchymal stem cells (MSCs) support axon regeneration across artificial nerve bridges but their differentiative capacity and ability to promote nerve regeneration remains unclear. In this study, MSCs isolated from bone marrow of Sprague–Dawley rats were characterized by plastic adherence and pluripotency towards mesodermal lineages. Isolated undifferentiated MSCs (uMSCs) were stimulated towards a Schwann cell (SC) phenotype using specific growth factors, and cell marker analysis was performed to verify SC phenotype in vitro. Differentiation resulted in temporally dependent positive immunocytochemical staining for the SC markers, glial fibrillary acidic protein (GFAP), S100, and nerve growth factor receptor (NGFR), with maximal marker expression achieved after 6 days of treatment with differentiation media. Quantitative analysis demonstrated that ~ 50% of differentiated MSCs (dMSCs) have a SC phenotype. Using an indirect co-culture system, we compared the ability of dorsal root ganglion (DRG) cells to extend neurites in indirect contact with uMSCs and dMSCs as compared to SCs. The mean values of the longest length of the DRG neurites were the same for the dMSCs and SCs and significantly higher than the uMSC and DRG mono-culture systems (p < 0.05). In vivo, compared to an empty conduit, dMSC seeded collagen nerve conduits resulted in a greater number of sciatic motoneurons regenerating axons through the conduit into the distal nerve stump. We conclude that bone marrow-derived MSCs differentiate into a SC-phenotype that expresses SC markers transiently and sufficiently to support limited neurite outgrowth in vitro and axonal regeneration equivalent to that of SCs in vitro and in vivo. The nerve autograft remains the most effective conduit for supporting regeneration across nerve gaps.     

富血小板血浆诱导骨髓间充质干细胞结合化学萃取去细胞神经修复坐骨神经缺损

背景：周围神经损伤早期许旺细胞尚未大量分裂增殖,此时由于解剖连续性的中断,通过轴浆逆向运输提供的营养因子骤减,缺乏神经营养因子支持的神经元有可能死亡,从而使周围神经不能再生或再生乏力。 目的：观察植入经富血小板血浆诱导的骨髓间充质干细胞结合去细胞神经修复坐骨神经缺损的效果。 方法：取新西兰大耳白兔制备坐骨神经缺损模型,随机抽签法分成4组：去细胞神经组,移植同种异体去细胞神经;骨髓间充质干细胞组,移植同种异体骨髓间充质干细胞结合化学萃取的同种异体去细胞神经：经诱导骨髓间充质干细胞组,移植经富血小板血浆诱导的同种异体骨髓间充质干细胞结合化学萃取的同种异体去细胞神经;自体神经组,移植自体神经。术后进行形态学观察与靶肌肉肌湿质量恢复率、运动神经传导速度、轴突直径和髓鞘厚度的检测。 结果与结论：经富血小板血浆诱导的骨髓间充质干细胞结合化学萃取的去细胞神经移植修复神经的靶肌肉肌湿质量恢复率、运动神经传导速度、轴突直径和髓鞘厚度及形态学观察明显优于移植单纯化学萃取的去细胞神经与骨髓间充质干细胞结合化学萃取的去细胞神经的效果,而与移植自体神经修复结果相似。说明经诱导后的骨髓间充质干细胞在体内具有许旺细胞的部分功能,可作为组织工程化外周神经的种子细胞,用于周围神经缺损的修复。     

Sciatic nerve regeneration across gaps within silicone chambers: long-term effects of NGF and consideration of axonal branching

We examined whether the short-term beneficial effects of nerve growth factor (NGF) upon regeneration are sustained over a prolonged period of time across 8-mm gaps within silicone chambers. Rat sciatic nerve regeneration both with and without NGF was examined after 10 weeks. Myelinated counts from the regenerated sciatic and distal tributary nerves were correlated to the numbers of motor and sensory neurons retrogradely labeled with horseradish peroxidase (HRP) applied distal to the regenerated segment. Regenerated sciatic and sural nerves were examined ultrastructurally for morphological analysis. Both regenerated groups by 10 weeks achieved essentially complete counts of myelinated axons in the distal tributary nerves and the regenerated segment of the sciatic nerve compared to the uninjured controls. There were similar numbers of retrogradely labeled sensory and motor neurons in the dorsal root ganglia (DRG) and lumbar spinal cord of both groups and, surprisingly, of the uninjured normal control group. Ultrastructural analysis demonstrated no difference in the distribution of axonal diameters or myelin thickness between the regenerated groups. In evaluating regeneration in experimental silicone chamber models, it is important to determine such parameters as the percentage of neurons that grow across the gap and the incidence of axonal sprouting. One can then make accurate assessments of experimental perturbations and predict whether they improve the naturally occurring regeneration through chambers. These results must ultimately be compared with equivalent determinations in the uninjured nerve. At 10 weeks there was essentially complete regeneration of both the NGF and control regenerative groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

靶肌肉注射人间充质干细胞对坐骨神经损伤保护性作用的电生理研究

目的探讨电生理在大鼠失神经支配的骨骼肌中移植间充质干细胞对坐骨神经损伤后修复中的作用。方法体外分离培养人间充质干细胞,经鉴定标记后备用。将36只SD大鼠随机分为肌肉注射干细胞组(实验组)、肌肉注射生理盐水组(对照组),每组18只,建立大鼠坐骨神经损伤模型,术后3d将干细胞和等量生理盐水注射到损伤侧坐骨神经支配的骨骼肌中。于移植后3、7、14、21、28、60d,观察坐骨神经功能指数(SFI)、腓肠肌肌电图(EMG)、运动神经传导速度(MCV),肌肉复合动作电位幅值(CMAP)检查。结果腓肠肌EMG实验组自发电位减少和动作电位出现时间均早于对照组。坐骨神经MCV和CMAP波幅呈恢复趋势。移植后:21d开始,实验组明显快于对照组(P<0.05),60d时,传导速度两组无显著性(P>0.05),波幅有显著性差异(P<0.05)。结论肌肉注射人间充质干细胞对坐骨神经损伤具有促修复作用。     

Morphological changes in spinal motor neurons giving rise to long-term regenerated sciatic nerve axons

Morphological properties of rat spinal motor neurons were examined 14-16 months following unilateral sciatic nerve crush and compared to the properties observed in neurons contralateral to injury and in cord segments from age-matched control rats. Regenerated and control motor neurons were identified by retrograde labelling with HRP applied to sciatic nerves distal to the site of crush or at a comparable location in control nerves. Many of the experimental motor neurons were enlarged and had thickened dendritic processess compared to the finer dendrites seen in control cells. Mean cell area ipsilateral to the crush lesions was larger than mean control cell area (P-value less than 0.001) despite representation of all control cell areas in the regenerated population. These data suggest that persistent or continued morphological abnormalities occur in mammalian motor neurons following simple sciatic crush injury when examined at extended times beyond the period of axonal regeneration and clinical recovery.     

脐带间充质干细胞与许旺细胞共移植修复大鼠坐骨神经缺损

Previous research has demonstrated that cotransplantation of umbilical cord mesenchymal stem cells (UCMSCs) and Schwann cells (SCs) can repair spinal nerve injury, but few studies have investigated their use in peripheral nerve regeneration. In the present study, we cotransplanted UCMSCs and SCs to repair 5-mm left sciatic nerve defects in rats, and compared the effects of UCMSCs + SCs transplantation with UCMSCs or SCs transplantation alone. After UCMSCs + SCs transplantation, nerve conduction velocity of the left sciatic nerve and gait were both improved. Retrograde tracing analysis demonstrated that the mean count of fluorogold-labeled neurons, as well as the mean axon count and axon density, were significantly greater in the left sciatic nerve after UCMSCs + SCs transplantation, compared with UCMSCs or SCs transplantation alone. Improvements in conduction velocity and increased sheath thickness in the left sciatic nerve were similar after UCMSCs transplantation and UCMSCs + SCs transplantation. These findings suggest that UCMSCs transplantation can promote the repair of sciatic nerve defects to some extent, but that combined UCMSCs + SCs transplantation has a significantly greater regenerative effect.     

BMSCs移植对大鼠脑梗死后神经功能恢复及Nogo-A表达的影响

目的探讨骨髓间充质干细胞（Bone Marrow-derived mesenchymal stem cells,BMSCs）静脉移植对大鼠脑梗死后神经功能恢复及对Nogo-A表达的影响。方法将大鼠随机分成假手术组、模型对照组、溶剂对照组和移植组。全骨髓贴壁法分离培养大鼠BMSCs,线栓法制作大鼠MCAO模型;移植组自尾静脉注射BMSCs悬液,溶剂对照组注射磷酸盐缓冲液;造模成功后第3、7、14和21 d通过神经功能缺损程度评分,观察其恢复状况;RT-PCR法检测Nogo-AmRNA的表达水平,免疫组化方法检测Nogo-A蛋白的表达水平。结果移植组第7、14和21 d神经功能恢复优于对照组;移植组第3、14和21 d脑组织损伤区周边组织中Nogo-AmRNA表达水平和Nogo-A蛋白的表达水平较对照组降低（P〈0.05）。结论 BMSCs移植可促进大鼠脑梗死后的神经功能恢复,其作用机制可能与下调Nogo-A的表达水平有关。     

骨髓间充质干细胞移植治疗对大鼠脑梗死后神经再生抑制因素的影响

目的探讨骨髓间充质干细胞(BMSCs)静脉移植对大鼠脑梗死后Nogo-A、少突胶质细胞髓磷脂糖蛋白(OMgp)和髓磷脂相关糖蛋白(MAG)蛋白的影响。方法实验动物分成假手术组、损伤对照组、溶剂对照组和移植组,各组再分为3d、7d、14d和21d组。全骨髓贴壁法分离培养大鼠BMSCs,线栓法制作大鼠脑梗死模型。移植组自大鼠尾静脉注射BMSCs悬液1ml,溶剂对照组注射磷酸盐缓冲液(PBS)。对各组动物进行神经功能缺损程度评分,免疫组化方法检测Nogo-A、OMgp和MAG的表达水平。结果移植组7、14和21d神经功能恢复优于对照组;移植组术后3、14和21d Nogo-A蛋白表达较对照组降低(P<0.05);移植组7、14和21d OMgp蛋白表达较对照组降低(P<0.05);移植组术后3、7、14和21d MAG蛋白表达较对照组降低(P<0.05)。结论 BMSCs移植可促进大鼠脑梗死后的神经功能恢复,其作用机制与下调Nogo-A、OMgp和MAG的表达有关。     

Mesenchymal stem cells expressing neural antigens instruct a neurogenic cell fate on neural stem cells

The neurogenic response to injury in the postnatal brain is limited and insufficient for restoration of function. Recent evidence suggests that transplantation of mesenchymal stem cells (MSCs) into the injured brain is associated with improved functional recovery, mediated in part through amplification in the endogenous neurogenic response to injury. In the current study we investigate the interactions between bone marrow-derived MSCs and embryonic neural stem cells (NSCs) plus their differentiated progeny using an in vitro co-culture system. Two populations of MSCs were used, MSCs induced to express neural antigens (nestin+, Tuj-1+, GFAP+) and neural antigen negative MSCs. Following co-culture of induced MSCs with differentiating NSC/progenitor cells a significant increase in Tuj-1+ neurons was detected compared to co-cultures of non-induced MSCs in which an increase in astrocyte (GFAP+) differentiation was observed. The effect was mediated by soluble interactions between the two cell populations and was independent of any effect on cell death and proliferation. Induced and non-induced MSCs also promoted the survival of Tuj-1+ cell progeny in long-term cultures and both promoted axonal growth, an effect also seen in differentiating neuroblastoma cells. Therefore, MSCs provide instructive signals that are able to direct the differentiation of NSCs and promote axonal development in neuronal progeny. The data indicates that the nature of MSC derived signals is dependent not only on their microenvironment but on the developmental status of the MSCs. Pre-manipulation of MSCs prior to transplantation in vivo may be an effective means of enhancing the endogenous neurogenic response to injury.     

NT-3转染骨髓间充质干细胞对脑缺血再灌注的机制研究

目的研究神经营养素-3(neurotrophin-3,NT-3)转染的骨髓间充质干细胞(BMSCs)移植对脑缺血再灌注损伤的作用机制。方法制作脑缺血再灌注损伤模型,将60只大鼠根据注射物不同分为3组:生理盐水对照组、BMSCs组和NT-3+BMSCs组(n=20),观察不同时间3组大鼠的神经学功能评分、脑组织光镜观察、TUNEL法检测神经元细胞的凋亡及丙二醛含量情况。结果 BMSCs+NT-3组移植后大鼠神经学功能评分较BMSCs组低,而BMSCs组较NS组较低,两组间比较均有统计学意义(P0.05);BMSCs+NT-3组脑组织光镜观察细胞形态学变化最轻;BMSCs组神经元凋亡较NS组减少,BMSCs+NT-3组的神经元凋亡数量较BMSCs组减少,两组间比较均有统计学意义(P0.05);NS组丙二醛(MDA)含量明显高于BMSCs组(P0.05);而BMSCs+NT-3转染组明显低于BMSCs组(P0.05)。结论大鼠BMSCs经NT-3转染后相互促进,移植于急性脑缺血再灌注损伤通过减缓神经元细胞凋亡、降低丙二醛含量抑制自由基的脂质过氧化反应进行修复。     

Inhibitor of DNA binding 2 accelerates nerve regeneration after sciatic nerve injury in mice

Inhibitor of DNA binding 2 (Id2) can promote axonal regeneration after injury of the central nervous system. However, whether Id2 can promote axonal regeneration and functional recovery after peripheral nerve injury is currently unknown. In this study, we established a mouse model of bilateral sciatic nerve crush injury. Two weeks before injury, AAV9-Id2-3×Flag-GFP was injected stereotaxically into the bilateral ventral horn of lumbar spinal cord. Our results showed that Id2 was successfully delivered into spinal cord motor neurons projecting to the sciatic nerve, and the number of regenerated motor axons in the sciatic nerve distal to the crush site was increased at 2 weeks after injury, arriving at the tibial nerve and reinnervating a few endplates in the gastrocnemius muscle. By 1 month after injury, extensive neuromuscular reinnervation occurred. In addition, the amplitude of compound muscle action potentials of the gastrocnemius muscle was markedly recovered, and their latency was shortened. These findings suggest that Id2 can accelerate axonal regeneration, promote neuromuscular reinnervation, and enhance functional improvement following sciatic nerve injury. Therefore, elevating the level of Id2 in adult neurons may present a promising strategy for peripheral nerve repair following injury. The study was approved by the Experimental Animal Ethics Committee of Jinan University (approval No. 20160302003) on March 2, 2016.

Chinese Library Classification No. R456; R745; R364.3+3     

骨髓间充质干细胞促进中脑前体细胞增殖及定向分化的实验研究

目的 观察BMSCs对胚胎腹侧中脑前体细胞(VMP)体外扩增和定向分化的影响,并分析其可能的营养机制.方法 分别取胎龄11d大鼠胚胎VMP、成年大鼠BMSCs进行体外培养,并建立二者的共培养体系.体外扩增7 d的VMP分为对照组、BMSCs分化液组、BMSCs+VMP共培养分化液组,分别加入普通分化液、BMSCs分化液、BMSCs+VMP共培养分化液进行诱导分化.观察细胞生长情况.分化期末行免疫荧光染色,分析比较3组细胞中酪氨酸羟化酶(TH)阳性细胞占总细胞数的比例.结果诱导分化7 d后,对照组、BMSCs分化液组和BMSCs+VMP共培养分化液组中细胞数分别较培养前扩增(44.13±4.75)倍、(60.63±5.25)倍、(64.00±7.63)倍,TH阳性细胞比例分别为(18.76±5.20)%、(23.49±4.10)%、(28.08±5.42)%,比较差异有统计学意义(P<0.05).结论 BMSCs能够通过分泌营养因子有效促进VMP增殖并定向分化为多巴胺能神经元.     

Transplantation of bone marrow mesenchymal stem cells reduces lesion volume and induces axonal regrowth of injured spinal cord

It has been demonstrated that transplantation of bone marrow mesenchymal stem cells (BMSCs) improves recovery of injured spinal cord in animal models. However, the mechanism of how BMSCs promote repair of injured spinal cord remains under investigation. The present study investigated the neural differentiation of BMSCs, the lesion volume and axonal regrowth of injured spinal cord after transplantation. Seven days after spinal cord injury, 3 × 10⁵ BMSCs or PBS (control) was delivered into the injury epicenter of the spinal cord. At 8 weeks after spinal cord injury, transplantation of BMSCs reduced the volume of cavity and increased spared white matter as compared to the control. BMSCs did not express the cell marker of neurons, astrocytes and oligodendrocytes in injured spinal cord. Transmission electron microscopic examination displayed an increase in the number of axons in BMSC rats. The effect of BMSCs on growth of neuronal process was further investigated by using a coculture system. The length and the number of neurites from spinal neurons significantly increased when they cocultured with BMSCs. PCR and immunochemical analysis showed that BMSCs expressed brain‐derived neurotrophic factor (BDNF) and glia cell line‐derived neurotrophic factor (GDNF). These findings demonstrate that transplantation of BMSCs reduces lesion volume and promotes axonal regrowth of injured spinal cord.     

Bone marrow-derived mesenchymal stem cells expressing the bFGF transgene promote axon regeneration and functional recovery after spinal cord injury in rats

Abstract

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Objective: To investigate neurological effects of transplanting bone marrow-derived mesenchymal stem cells (BMSCs) transfected with the basic fibroblast growth factor (bFGF) gene in spinal cord-injured rats.

Methods: Ninety-six male adult Sprague-Dawley rats were randomized into four groups: (1) pcDNA3·1-bFGF group; (2) pcDNA3·1 group; (3) BMSCs group; and (4) vehicle control (DMEM) group. After the rat model of acute spinal cord injury (SCI) was established, 1×10⁶ BMSCs or cells transfected with pcDNA3·1-bFGF or pcDNA3·1 were injected into rats of groups 1-3. At days 1, 7, 14, and 21 after injection, the Basso-Beattie-Bresnahan (BBB) locomotor rating scale was used to evaluate recovery of motor function. Expression changes of bFGF, myelin basic protein (MBP), and NF200 were examined by immunohistochemistry.

Results: The BBB score of DMEM group was significantly lower than those of groups 1-3 (P<0·05), but the score of pcDNA3·1-bFGF group was significantly higher than that of BMSCs group or pcDNA3·1 group at day 14 or 21 after injection (P<0·01). The number of bFGF-positive neurons in rats of pcDNA3·1-bFGF group was significantly higher than those of groups 1-3 at any time point (P<0·05). The optical density values of NF200-positive neurons and MBP-positive MBP axons in rats of pcDNA3·1-bFGF group were significantly higher than those of groups 1-3 at day 7 or 14 after injection (P<0·05).

Conclusions: bFGF gene-modified BMSCs not only effectively promoted axonal outgrowth but also enhanced recovery of neurological function after SCI in rats, and may be a good candidate to evaluate gene therapy of SCI in man.     

再程序化脂肪干细胞移植治疗大鼠脊髓损伤的机制

目的制备再程序化脂肪干细胞(ADSCs),并在体研究再程序化ADSCs移植入大鼠脊髓损伤模型后促进损伤脊髓神经功能恢复的作用和机制。方法体外培养、纯化和鉴定大鼠ADSCs,并利用慢病毒包装神经元生成素2(Ngn2)基因转染ADSCs制备再程序化干细胞。体内实验将48只雌性SD大鼠随机分成3组:SCI对照(A)组、单纯ADSCs移植(B)组和Ngn2-ADSCs移植(C)组。采用BBB评分评价大鼠运动功能,并通过HE染色、免疫组化和免疫荧光等方法检测脊髓组织学改变和相关蛋白的表达水平,进而观察实验动物脊髓功能恢复情况。结果 Ngn2-ADSCs移植组在运动功能评分、胶质瘢痕的形成、脊髓损伤后病理变化和分泌神经营养因子BDNF和VEGF蛋白含量明显优于其他组。结论 Ngn2-ADSCs移植后能有效地存活,并分化为神经细胞,抑制胶质瘢痕形成,减小脊髓损伤空洞,增加BDNF和VEGF表达,最终促进SCI大鼠的运动功能恢复,较单纯应用ADSCs能更好地促进SCI修复。