Intracarotid transplantation of bone marrow stromal cells increases axon-myelin remodeling after stroke

The present study investigates the induction of axon and myelin remodeling as a possible mechanism by which treatment of stroke with bone marrow stromal cells improves neurological functional recovery. Adult male Wistar rats were subjected to 2 h of middle cerebral artery occlusion, followed by an injection of 2 x 10(6) rat bone marrow stromal cells or phosphate-buffered saline into the internal carotid artery 24 h later. Animals were killed at 28 days after stroke. Functional tests, histo- and immunohistochemical staining were performed. Significant functional recovery was found after bone marrow stromal cell administration in all the three tests performed (modified neurological severity score, adhesive-removal and corner tests). Bone marrow stromal cell treatment markedly increased vessel sprouting, synaptophysin expression and NG2 positive cell numbers and density in the cortical peri-infarct area. In bone marrow stromal cell-treated rats, the number of Ki-67 positive proliferating cells and oligodendrocyte precursor cells in the corpus callosum increased significantly in concert with the enhancement of the areas of the corpus callosum in both hemispheres. These results suggest that bone marrow stromal cells facilitate axonal sprouting and remyelination in the cortical ischemic boundary zone and corpus callosum, which may underlie neurological functional improvement caused by bone marrow stromal cell treatment.     

Osteogenic differentiation and angiogenesis with cocultured adipose-derived stromal cells and bone marrow stromal cells

The purpose of this study was to determine the influence of cocultured adipose-derived stromal cells (ASCs) in enhancing the osteogenic differentiation and angiogenesis of bone marrow stromal cells (BMSCs) as well as the underlying mechanism and the optimal ratio. Two in vitro coculture models, segregated cocultures using transwell and mixed cocultures, were employed to assess the indirect and direct effects of coculture respectively. Coculture was carried out for 14 days using 1 × 10⁵ BMSCs and ASCs of variable number. BMSCs, ASCs, or both were seeded in PLGA scaffold and implanted in the subcutaneous tissue of 25 nude mice for in vivo analysis of angiogenesis. To evaluate the orthotopic bone formation, critical size calvarial defects were created on 20 mice, and implanted with hydroxyapatite/β-tricalcium phosphate granules plus BMSCs, ASCs, or both. From both transwell and mixed coculture model, 1 × 10⁵ BMSCs cocultured with 0.5 × 10⁵ ASCs showed significantly greater osteogenic differentiation and mineralization than BMSCs alone. The mixed ASC/BMSC coculture at or above a ratio of 0.5/1 showed increased secretion of vascular endothelial growth factor (VEGF), and induced effective tube formation from human umbilical vein endothelial cells, which were comparable to ASCs. Cytokine profiling assay and gene expression study showed elevated levels of angiogenic factors VEGF and CXCL1, osteogenic factor Wnt5a as well as transforming growth factor (TGF)-βR1 and SMAD3 from BMSCs when cocultured with ASCs. After 5 weeks of implantation, polylactic-co-glycolic acid (PLGA)-ASCs-BMSCs had a number of vascular structures comparable to PLGA-ASCs and significantly greater than PLGA-BMSCs. Calvarial defects treated with ceramic/BMSCs/ASCs had greater area of repair and better reconstitution of osseous structure than the defects treated with ceramic/ASCs or ceramic/BMSCs after 10 weeks. In conclusion, ASCs added to BMSCs promoted osteogenesis and angiogenesis at the optimal ASC/BMSC ratio of 0.5/1.     

大鼠骨髓源性血管内皮祖细胞体外培养分化及鉴定

目的：探索大鼠骨髓源性血管内皮祖细胞（EPCs）的培养、诱导分化及鉴定方法。方法：冲洗大鼠骨髓腔,梯度密度离心法获得单个核细胞,内皮细胞培养液EGM-2MV培养,通过细胞形态,免疫组化和免疫荧光检测CD34、VEGFR-2、vWF,CD133,摄取Dil-ac-LDL和结合FITC-Lectin-UEA-1,超微结构及染色体核型分析进行鉴定。结果：新分离的骨髓单个核细胞呈圆形,大小不一;48h后部分细胞开始贴壁,呈梭形、纺锤形或不规则形;4～8d呈细胞集落或线状排列;9～11d接近融合,呈典型鹅卵石样外观。贴壁细胞CD34、CD31、VEGFR-2、vWF、CD133均表达阳性并呈动态变化,能够摄取Dil-ac-LDL和结合FITC-Lectin-UEA-1,透射电镜见特征性Weible-Palade小体,能稳定保持二倍体核型。结论：本实验初步建立了一套大鼠骨髓血管内皮祖细胞分离、培养、诱导分化及鉴定方法体系。     

骨髓基质细胞移植促进脑缺血大鼠海马巢蛋白的表达

目的:探讨移植骨髓基质细胞(BMSCs)对永久性局灶性脑缺血大鼠海马巢蛋白表达的影响。方法:制备永久性局灶性脑缺血大鼠模型,分为PBS对照组和治疗组,再将每组动物随机均分为脑缺血后7d和14d亚组。PBS对照组在脑缺血后1d注射PBS,治疗组在脑缺血后第1日移植BMSCs。Zausinger六分法检测神经功能恢复情况;免疫组织化学方法检测大鼠海马的巢蛋白表达。结果:在脑缺血后第7日和第14日两个时相点,治疗组的神经功能评分均较高,与PBS对照组之间存在显著性差异;齿状回的颗粒细胞下层、颗粒细胞层和海马锥体细胞层均有巢蛋白表达,在脑缺血后第14日,治疗组的大鼠患侧海马的巢蛋白阳性细胞较对照组表达高,存在显著性差异。结论:BMSCs可以改善脑缺血大鼠的神经功能;促进海马内神经干细胞或反应性星形胶质细胞增殖可能为其修复缺血脑损伤的机制之一。     

大鼠骨髓内皮祖细胞的分离、培养及鉴定

目的 研究大鼠骨髓来源的内皮祖细胞(EPC)的分离、鉴定、培养方法以及向内皮细胞分化的诱导条件.方法 密度梯度离心法分离SD大鼠股骨及胫骨单个核细胞,经差速贴壁后取2次贴壁细胞置于纤连蛋白铺被的培养板中.在血管内皮生长因子(VEGF)、碱性成纤维细胞生长因子(bFGF)及表皮生长因子(EGF)诱导下培养两周,观察其形态学改变,以免疫细胞化学染色及Dil-acLDL、FITC-UEA-1双荧光染色法对其进行鉴定.结果 贴壁细胞呈现铺路石、团簇样生长,呈梭形、线样排列特殊形态.免疫细胞化学结果显示,贴壁细胞CD133、CD34、Flk-1、血管性假血友病因子(vWF)在不同时段呈阳性表达.诱导培养第2天,CD133阳性表达率为(79.4±4.5)%.自诱导培养的第6天开始,Flk-1与vWF呈高表达,阳性率为(74.2±3.5)%和(72.2±4.3)%.结论 用Percoll密度梯度离心法在VEGF、bFGF及EGF培养体系下可以获得较高纯度的EPC,该细胞具有内皮细胞的特性,经过体外诱导可以分化为内皮细胞.     

双特异抗体增效内皮祖细胞移植促进心肌血管新生

目的探讨在双特异抗体(BiAb)的辅助下,内皮祖细胞(EPCs)移植可否更好的定向归巢大鼠缺血心肌促进血管新生。方法体外分离培养鉴定SD大鼠骨髓源性内皮祖细胞;开胸结扎SD大鼠冠状动脉左前降支制备心肌梗死模型;以anti-CD34(能识别内皮祖细胞)和抗肌凝蛋白轻链抗体(AMLCA)(能特异性结合缺血心肌)2种抗体,化学交联法制备BiAb(CD34×AMLCA)。将此BiAb与EPCs经尾静脉输入心肌梗死大鼠(EPCs+BiAb组),另设单纯EPCs移植组、单纯BiAb组、对照组。细胞移植35 d后M型超声心动图检测大鼠左室收缩功能,免疫组织化学法行5-Brdu及VIII因子检测,实时荧光定量PCR及Western blot检测大鼠心肌VEGF mRNA与蛋白表达。结果与其余组相比,EPCs+BiAb组射血分数及短轴缩短率增加,心梗区周围5-BrdU阳性细胞数及微血管密度增加,心肌VEGF mRNA与蛋白表达增加(P<0.05)。结论 CD34×AMLCA双特异抗体可增效大鼠骨髓源性内皮祖细胞定向归巢到大鼠缺血心肌,改善心功能,更好的促进血管新生。     

The role of fucosylation in the promotion of endothelial progenitor cells in neovascularization and bone repair

Bone marrow-derived endothelial progenitor cells (EPCs) are being tested as a therapy to treat a variety of ischemic diseases. Poor homing to targeted tissues is one of the major factors limiting the therapeutic efficacy of EPCs. Here, we show that human cord blood-derived EPCs expressed little sialyl Lewis X (sLe^x) antigen that is necessary for selectin-mediated cell–cell interactions. Expression of α1,3-fucosyltransferase VI (FucT VI) in the EPCs enhanced sLe^x synthesis, E- and P-selectin-binding, and EPC adhesion to tumor necrosis factor-α-stimulated human umbilical vein endothelial cells in culture. In a mouse model of hind limb ischemia, in which EPCs were injected intravenously, FucT VI expression increased EPC homing, neovascularization, and blood flow in ischemic muscles. In another mouse model of femoral fracture, FucT VI-expressing EPCs were more efficient than control EPCs in targeting to peri-fracture tissues to enhance angiogenesis, blood flow and bone repair. These results indicate that fucosylated EPCs may be used to as an improved cellular source to treat ischemic diseases.     

骨髓基质细胞对"缺血/再灌注"海马片的保护作用及其机制

目的:探讨骨髓基质细胞对"缺血/再灌注"海马片的保护作用及其机制。方法:建立新生大鼠海马片"缺血/再灌注"模型。取成年大鼠骨髓, 培养、分离、纯化骨髓基质细胞。观察海马片细胞死亡及骨髓基质细胞表达脑源性神经营养因子(BDNF)的动态变化。结果:"缺血"后"再灌注"1、3、7d, 碘化丙啶荧光排斥法显示海马片大量细胞死亡。与骨髓基质细胞联合培养后1、3、7d, 仅有少量细胞死亡。加入抗BDNF抗体后, 骨髓基质细胞对"缺血/再灌注"海马片的保护作用明显减弱。正常骨髓基质细胞在自然条件下微弱表达BDNF;与"缺血/再灌注"海马片联合培养后骨髓基质细胞表达BDNF逐渐增加, 在第3、7d更明显;与正常海马片联合培养的骨髓基质细胞仅出现持续低水平的BDNF表达。结论:骨髓基质细胞可以减少缺血海马片细胞死亡;"缺血/再灌注"海马片与骨髓基质细胞联合培养可以促进骨髓基质细胞表达BDNF, 可能由此发挥对缺血海马片的保护作用。     

犬骨髓内皮祖细胞生物学特性及诱导分化

目的:探讨犬骨髓内皮祖细胞(EPCs)随培养时间延长其生物学特性变化及向内皮细胞(ECs)分化能力。方法:免疫微珠分选方法纯化犬骨髓CD14 细胞,EGM-MV2条件培养基培养,于不同时间检测EPCs的生物学特性;将存活至8周的EPCs以分化培养基(M199 20%胎牛血清 VEGF)诱导培养,检测ECs表面标志的表达。结果:早期EPCs为分选后8代之前的EPC,体积略小,类圆形,60%融合时呈串珠样排列,表达CD133、CD14;晚期EPCs由表达VE-cadherin、KDR、CD14的早期EPCs分化而来,形态为多边形,分泌活动明显加强,表达CD133、VE-cadherin、CD14和KDR;诱导分化细胞呈鹅卵石样外观,表达Ⅷ因子、CD31。结论:犬骨髓EPCs随培养时间呈现不同生物学特性,早期EPCs不稳定,晚期EPCs显示出更稳定的生物学特性,能够分化为ECs,是血管组织工程学研究良好的种子细胞。     

骨髓间质细胞中组织定向干细胞的鉴定

目的:验证骨髓中存在组织定向干细胞(TCSCs),为心血管组织工程提供理想的种子细胞来源。方法:采用SDF-1α梯度趋化从骨髓中分离CXCR4阳性细胞,免疫细胞化学法检测CXCR4与PDGFR-β表达,流式细胞仪检测PDGFR-β阳性细胞,从而确定平滑肌祖细胞(SMPCs)的比例;从骨髓分离培养内皮祖细胞(EPCs),免疫细胞化学和流式细胞仪检测FLK-1、CD34、CXCR4与vWF的表达情况。结果:SDF-1α趋化分离出的细胞几乎都为CXCR4阳性,其中4·67%的细胞呈PDGFR-β阳性;EPCs形态圆形或近三角形贴壁生长,原代细胞CXCR4、VEGFR-2、CD34明显阳性,传代细胞vWF阳性。结论:在骨髓基质细胞中存在SMPCs和EPCs等TCSCs。     

Paracrine mechanisms of endothelial progenitor cells in vascular repair

Endothelial progenitor cells (EPCs) play an important role in repairing damaged blood vessels and promoting neovascularization. However, the specific mechanism of EPCs promoting vascular repair is still unclear. Currently, there are two different views on the repair of damaged vessels by EPCs, one is that EPCs can directly differentiate into endothelial cells (ECs) and integrate into injured vessels, the other is that EPCs act on cells and blood vessels by releasing paracrine substances. But more evidence now supports the latter. Therefore, the paracrine mechanisms of EPCs are worth further study. This review describes the substances secreted by EPCs, some applications based on paracrine effects of EPCs, and the studies of paracrine mechanisms in cardiovascular diseases--all of these are to support the view that EPCs repair blood vessels through paracrine effects rather than integrating directly into damaged vessels.     

经肾动脉自体骨髓干细胞移植治疗急性肾小管坏死的实验研究

目的：采用经肾动脉灌注移植兔自体骨髓干细胞，观察自体骨髓干细胞移植对缺血再灌注（I/R）后急性肾小管坏死肾功能的作用及其机制。方法:28只日本大耳白兔采集骨髓，分离自体骨髓干细胞，5-溴-2-脱氧尿嘧啶核苷(5-bromo-2-deoxyuridine, BrdU)标记。全部实验兔建立肾脏I/R后随机分为移植组和对照组。移植组于肾血流恢复后经肾动脉灌注自体骨髓干细胞悬液，对照组同样方法注射等体积生理盐水。分别于I/R前和I/R后第1、3、5、7、14、21、28 d静脉采血，检测血清肌酐（SCr）和尿素氮（BUN），相同时点取肾组织行普通病理及BrdU免疫组化观察。结果:I/R后第1 d和第3 d 2组动物SCr、BUN均达到最高水平，以后逐渐下降；第7 d后移植组SCr及BUN水平逐渐低于对照组，到实验观察结束时的第28 d，对照组SCr和BUN分别为（135.6±32.5）μmol/L和（10.9±2.5）mmol/L，移植组SCr和BUN分别为（90.1±11.1）μmol/L和（8.0±1.5）mmol/L，2组间有显著差异（P<0.05）。普通病理观察，I/R后肾小管上皮细胞变性、坏死甚至脱落， BrdU免疫组化染色显示移植组于细胞移植后第5、7 d肾小管BrdU阳性染色并持续至实验结束，对照组阴性。结论:骨髓干细胞移植可以在一定程度上加速急性肾小管坏死后肾功能修复，自体骨髓干细胞移植是1种加速急性肾小管坏死后修复的安全而有效的方法。     

静脉移植骨髓基质干细胞对脑缺血大鼠神经功能及神经细胞凋亡的影响

目的： 探讨骨髓基质干细胞静脉移植后进入大鼠局灶性缺血脑内的短期存活情况及其对脑缺血大鼠神经功能的影响。方法: 将BrdU标记大鼠骨髓基质干细胞后，经尾静脉注射到局灶性脑缺血大鼠体内，分别在脑缺血术后1 d、7 d、14 d和28 d通过神经功能评分观察移植后大鼠神经行为学变化情况，通过组织学方法观察移植到脑内的骨髓基质干细胞存活状态和脑内缺血区与非缺血区神经细胞死亡情况，用RT-PCR方法观察到骨髓基质干细胞表达细胞因子及神经营养因子。结果: 骨髓基质干细胞移植组在14 d和28 d大鼠神经功能评分显著低于对照组（P<0.05），神经功能得到明显改善。静脉移植的骨髓基质干细胞在移植的1 d主要分布在损伤侧大脑中动脉周围组织间质中，在第3d沿着损伤侧的下丘脑迁移至海马的CA1(cornu ammonis 1, CA1)区；骨髓基质干细胞移植组大鼠梗死灶周围的死亡细胞在14 d和28 d明显少于对照组（P<0.05）。结论: 经静脉注射移植骨髓基质干细胞能迁移到损伤区并能够明显促进局灶性脑缺血大鼠的神经行为功能恢复；抗凋亡、分泌神经营养因子改善微环境、动员神经干细胞并迁移至缺血区可能是静脉注射骨髓基质干细胞治疗局灶性脑缺血的机制。     

Hypoxia increases VEGF-A production by prostate cancer and bone marrow stromal cells and initiates paracrine activation of bone marrow endothelial cells

Hypoxia develops at sites of rapid cancer growth near sites of poorly organized vasculature. Heparin binding growth factors (HBGFs) support neoangiogenesis of tumors. We examined the effect of culturing bone-targeted, metastatic C4-2B prostate cancer cells and bone stromal derived HS27a cells under hypoxic conditions on expression of vascular endothelial growth factor (VEGF) family members. A sealed chamber infused with 1% (hypoxic) or 20% (normoxic) O(2) was used. Both cell lines produced VEGF-A in normoxia, but little or no HB-EGF, another HBGF. HS27a cells produced low levels of FGF-2 and HGF, but little or none was secreted by C4-2B cells. Levels of VEGF-A in conditioned medium (CM) from both cell lines doubled when cultured in hypoxia. Similar changes in VEGF-A mRNA levels were seen. Receptor expression was unchanged by hypoxia. Changes in VEGF-A expression during hypoxia were preceded by nuclear accumulation of hypoxia inducible factor-1alpha (HIF-1alpha). Bone marrow endothelial (BME) cells express high levels of VEGFR2/flk-1, and are targets of VEGF-A induced neovascularization. BME cells proliferated in response to treatment with HS27a CM, but not C4-2B CM. BME cells formed tube-like angiogenic structures on growth factor reduced Matrigel in response to CM from HS27a or C4-2B cells. This response was greater when CM was produced under hypoxia, and was reduced by VEGF-A or FGF-2 neutralizing antibodies. We conclude that hypoxia triggers a physiologically relevant increase in VEGF-A by prostate cancer and bone marrow stromal cells which involves a paracrine loop that recruits and activates BME to support tumor neovascularization-related processes.     

转IL—2基因的骨髓基质细胞对骨髓移植后免疫功能重建的促进作用

目的探讨了用逆转录病毒载体转入小鼠IL-2基因的基质细胞系QXMSC1对异基因骨髓移植后免疫功能重建的促进作用.方法将小鼠IL-2cDNA片段连接到逆转录病毒载体PLXSN上,构建重组逆转录病毒载体PL2SN(含小鼠IL-2cDNA).用磷酸钙共沉淀法将PL2SN转入单嗜性包装细胞系CRE,获得G418抵抗细胞株后,以上清感染双嗜性包装细胞系CRIP,G418筛选后获得高滴度的包装细胞系CRIPIL-2.感染NIH3T3细胞测定CRIPIL-2培养上清病毒滴度为3.4×105cfu/ml.感染骨髓基质细胞系QXMSC1(H-2d),G418筛选,有限稀释法得10个单克隆细胞株,选择表达IL-2最高的细胞株为实验用细胞QXMSC1IL-2,用于以后的实验.供体小鼠BALB/c(H-2d)骨髓以抗T细胞单抗anti-Thy1.2加补体去除骨髓中T细胞,受体小鼠C57BL/6(H-2b)经γ射线致死剂量照射后,输入供体骨髓1×107/只,同时输入基质细胞QXMSC1IL-25×105/只.在第30天、60天检测BMT小鼠脾细胞对LPS、ConA的反应,脾细胞产生IL-2的能力,BMT小鼠产生抗体生成细胞(PFC)的能力及产生DTH的能力.流式细胞仪检测了QXMSC1IL-2对BMT小鼠T细胞亚群的影响.结果电泳及酶切鉴定证实构建的PL2SN质粒.QXMSC1IL-2细胞系IL-2的分泌量为857U(1×106*24h).异基因骨髓移植,共输入QXMSC1IL-2能明显增加BMT小鼠脾细胞对LPS、ConA的反应.脾细胞产生IL-2的能力增强.PFC数目增加,DTH反应增强.T细胞亚群中CD4+/CD8+的比例有所恢复.结论转入IL-2的骨髓基质细胞系可促进骨髓移植后免疫功能重建.     

Therapeutic effect of co-transplantation of neuregulin 1-transfected-Schwann cells and bone marrow stromal cells on spinal cord hemisection syndrome

The aim of this present study is to evaluate the therapeutic effect of co-transplantation of neuregulin-1-transfected-Schwann cells (SCs) and bone marrow stromal cells (BMSCs) on a rat model of spinal cord hemi-section injuries (Brown–Séquard syndrome), which is relevant to human clinical spinal cord injury. Both in vivo and in vitro data we received demonstrated that co-transplantation BMSCs with NRG1-transfected SCs reduced the size of cystic cavities, promoted axonal regeneration and hind limb functional recovery in comparison with SCs or BMSCs transplantation alone or together, and this treatment could provide important insights into potential therapies of spinal cord hemi-section injuries.     

改良差时贴壁法分离培养鉴定小鼠骨髓间充质干细胞和内皮前体细胞

目的 探索同时从小鼠骨髓分离培养间充质干细胞(MSCs)与内皮前体细胞(EPCs)及对其鉴定的方法。方法 小鼠骨髓细胞经改良差时贴壁法分离,以48h为时间点,48h内贴壁细胞传至3代后行成骨、成软骨、成脂分化诱导实验,流式细胞术（FCM）检测其表面标记;48h后收集未贴壁细胞,传至3代后行血管形成实验,传至5代后行CD31免疫荧光细胞染色实验,FCM检测其表面标记。 结果 第3代48h内贴壁细胞可诱导分化为骨、软骨和脂肪细胞,FCM 检测Sca-1、CD29、CD45、CD11b 阳性率分别为（98.30±0.75）%,（97.47±1.32）%,（1.87±0.15）%,（1.03±0.71）%;第3代48h后贴壁细胞在基质胶上可形成血管样结构,第5代48h后贴壁细胞特异性表面抗原CD31呈阳性表达,FCM检测CD34、CD133、血管内皮生长因子受体（VEGFR2） 阳性率分别为（88.90±1.18）%,（92.73±2.90）%,（87.63±1.79）%。 结论 采用改良差时贴壁法可同时分离培养扩增小鼠骨髓 MSCs和 EPCs,且简便高效稳定可重复。     

骨髓基质细胞分泌蛋白的蛋白质质谱分析

目的通过Shotgun蛋白质组学分析,初步检测骨髓基质细胞(BMSCs)条件液中可能含有的蛋白质。方法将BMSCs条件液混匀后经超滤浓缩分为大于5kD和小于5kD两部分,并培养神经干细胞(NSCs),观察其后代中神经元、星形胶质细胞和少突胶质细胞的比例,鉴定出能调节NSCs分化的部分,并进行Shotgun蛋白质组学分析。结果BMSCs条件液分子量大于5kD的部分可以调节NSCs向神经元和少突胶质细胞方向分化,这部分条件液先经过聚丙烯酰胺凝胶电泳(SDS-PAGE)发现大部分蛋白集中在14kD以上,将蛋白条带酶解以后,经Shotgun分析共鉴定到456种蛋白质,其中154个相似蛋白质,17个假想蛋白质,56个未知蛋白质,剩余的229个蛋白质中大多为细胞骨架蛋白、分泌蛋白、信号转导蛋白、酶类和转运蛋白等。结论BMSCs分泌的多种蛋白质对NSCs的分化起调节作用,明确了BMSCs条件液中可能含有的成分。     

Dynamic changes of cell cycle elements in the ischemic brain after bone marrow stromal cells transplantation in rats

Transplantation of bone marrow stromal cells (BMSCs) improves animal neurological functional recovery after stroke. But the mechanism remains unclear. As cell cycle machinery plays an important role in stroke, we investigated the dynamic changes of cell cycle elements in a rat model of middle cerebral artery occlusion. We found the cell cycle markers, cdk4 along with its activator cyclin D1, and proliferating cell nuclear antigen (PCNA), increased after brain ischemia–reperfusion. Phosphorylation of the retinoblastoma protein (pRb, on ser-795), the cyclin D/cdk4 complex mutual target, was upregulated accordingly. However, intravenously administrated BMSCs facilitated cyclin D1, cdk4, and PCNA decrease in the ischemic cortex. Meanwhile, phospho-pRb (ser-795) was completely inhibited. On the contrary, endogenous cdk inhibitor p27 reduced before but enhanced after BMSCs treatment. These findings suggested BMSCs might modulate cell cycle progression in injured brain via downregulation of the cyclin D1/cdk4/pRb pathway as well as upregulation of p27 level. These results provide another way by which BMSCs may contribute to the recovery from stroke.     

骨髓基质干细胞向有功能性神经细胞诱导分化的研究进展

骨髓基质干细胞（BMSCs）是成体干细胞的一种,广泛存在于人体的间充质组织中,具有较强的自我复制能力和多向分化潜能;单独或联合使用某些诱导剂和细胞基因方面的干预,可使其在体外培养条件下向某一谱系细胞分化且不改变多向分化和增殖能力;同时具有独特的免疫学特征,是理想的组织工程种子细胞。近几年发现其在一定的条件下能够诱导分化为神经细胞,并具有神经细胞的结构和功能,将为神经系统疾病的治疗提供新的思路。着重对骨髓基质干细胞向神经细胞诱导分化及功能方面的研究进行综述。