BMP-IHH-mediated interplay between mesenchymal stem cells and osteoclasts supports calvarial bone homeostasis and repair

Calvarial bones are connected by fibrous sutures. These sutures provide a niche environment that includes mesenchymal stem cells(MSCs), osteoblasts, and osteoclasts, which help maintain calvarial bone homeostasis and repair. Abnormal function of osteogenic cells or diminished MSCs within the cranial suture can lead to skull defects, such as craniosynostosis. Despite the important function of each of these cell types within the cranial suture, we have limited knowledge about the role that crosstalk between them may play in regulating calvarial bone homeostasis and injury repair. Here we show that suture MSCs give rise to osteoprogenitors that show active bone morphogenetic protein(BMP) signalling and depend on BMP-mediated Indian hedgehog(IHH) signalling to balance osteogenesis and osteoclastogenesis activity. IHH signalling and receptor activator of nuclear factor kappa-Β ligand(RANKL) may function synergistically to promote the differentiation and resorption activity of osteoclasts. Loss of Bmpr1a in MSCs leads to downregulation of hedgehog(Hh) signalling and diminished cranial sutures. Significantly, activation of Hh signalling partially restores suture morphology in Bmpr1a mutant mice, suggesting the functional importance of BMP-mediated Hh signalling in regulating suture tissue homeostasis. Furthermore, there is an increased number of CD200+ cells in Bmpr1a mutant mice, which may also contribute to the inhibited osteoclast activity in the sutures of mutant mice. Finally, suture MSCs require BMPmediated Hh signalling during the repair of calvarial bone defects after injury. Collectively, our studies reveal the molecular and cellular mechanisms governing cell–cell interactions within the cranial suture that regulate calvarial bone homeostasis and repair.

A Multi-Center International Survey Related to the Nutritional Support after Hematopoietic Stem Cell Transplantation Endorsed by the ASIA Pacific Blood and Marrow Transplantation (APBMT)

Background: The nutritional support after hematopoietic stem cell transplantation (HSCT) has not been well established due to the scarcity of clinical trials. To conduct international clinical trials in Asia, we performed the questionnaire survey to investigate the current standard of nutritional support after HSCT. Method: We sent the questionnaire to the physicians nominated by the Asia Pacific Blood and Marrow Transplantation (APBMT) members of each country/ region. Result: We received 15 responses from 7 different countries/regions. The target calorie amount is 1.0 - 1.3 × basal energy expenditure (BEE) in 11 institutes when partial parenteral nutrition is used. When total parenteral nutrition (TPN) is used, the target calorie amount is 1.0 - 1.3 × BEE in 9 institutes and 1.3 - 1.5 × BEE in 4 institutes. Lipid emulsion is routinely used in 12 institutes. Multivitamins and trace elements are routinely added to TPN used in most institutes. It is still uncommon to use the immunonutrition. Blood glucose levels are routinely monitored in all institutes, but the target range varies (<110 in 2 institutes, <150 in 4 institutes, and <200 in 8 institutes). Conclusions: Basic nutritional support is similar in participating institutes. However, the target glucose level varies and the use of immunonutrition is rather rare. These points can be the theme of future clinical trials.

Expression change of stem cell-derived neural stem/progenitor cell sup-porting factor gene in injured spinal cord of rats

Objective To explore the expression change of stem cell-derived neural stem/progenitor cell supporting factor （SDNSF） gene in the injuried spinal cord tissues of rats, and the relation between the expressions of SDNSF and nestin. Methods The spinal cord contusion model of rat was established according to Allen＇s falling strike method. The expression of SDNSF was studied by RT-PCR and in situ hybridization （ISH）, and the expression of nestin was detected by immunochemistry. Results RT-PCR revealed that SDNSF mRNA was upregulated on day 4 after injury, peaked on day 8-12, and decreased to the sham operation level on day 16. ISH revealed that SDNSF mRNA was mainly expressed in the gray matter cells, probably neurons, of spinal cord. The immunohistochemistry showed that accompanied with SDNSF mRNA upregulation, the nestin-positive cells showed erupted roots, migrated peripherad and proliferation on the 8-day slice. However, the distribution pattern of these new cells was different from that of SDNSF-positive cells. Conclusion （1） SDNSF is expressed in the gray matter of spinal cord. The expression of SDNSF mRNA in the spinal cord varies with injured time. （2） The nestin-positive cells proliferate accompanied with spinal cord injury repair, but do not secrete SDNSF.

美国K-12整合性STEM教育框架:理念、课程路径与支持系统

美国整合性STEM教育框架基于STEM理念,阐明对整合性STEM的共识性理解,首次提供了涵盖K-12阶段的整合性STEM课程资源,绘制了STEM课程路线图,提供在课堂层次实施STEM的课程路线,为整合STEM方法的系统转型提供支持,以数据驱动STEM教学与评价,制定有效的STEM课程项目和STEM教师专业发展框架,推动整合性STEM课程实施与教学方法改革,培养学生运用STEM知识去解决真实问题,提高创新、批判性思维和解决问题的能力,培养21世纪技能。美国整合性STEM教育框架的课程理念、课程路径与课程支持系统,对我国在基础教育阶段推进STEM教育改革,开发全学段的STEM教育整体框架和课程路线图可以提供有益借鉴,包括基于标准的整合性STEM课程框架,赋能STEM教师的整合性教学实践和推动整合性STEM教育的系统性转变。

Pretreatment with scutellaria baicalensis stem-leaf total flavonoid prevents cerebral ischemia-reperfusion injury

Pretreatment with scutellaria baicalensis stem-leaf total flavonoid has protective effects against ischemia and attenuates myocardial ischemia-reperfusion injury. In this study, rats were given scutellaria baicalensis stem-leaf total flavonoid intragastrically at 50, 100, and 200 mg/kg per day for 7 days before focal cerebral ischemia-reperfusion injury models were established using the suture method. We then determined the protective effects of scutellaria baicalensis stem-leaf total flavon- oid pretreatment on focal cerebral ischemia-reperfusion injury. Results showed that neurological deficit scores increased, infarct volumes enlarged, apoptosis increased and Bcl-2 and Bax protein expression were upregulated at 24 hours after reperfusion. Pretreatment with scutellaria baicalensis stem-leaf total flavonoid at any dose lowered the neurological deficit scores, reduced the infarct volume, prevented apoptosis in hippocampal cells, attenuated neuronal and blood-brain barrier damage and upregulated Bcl-2 protein expression but inhibited Bax protein expression. Doses of 100 and 200 mg/kg were the most efficacious. Our findings indicate that pretreatment with scutel- laria baicalensis stem-leaf total flavonoid at 100 and 200 mg/kg can improve the neurological func- tions and have preventive and protective roles after focal cerebral ischemia-reperfusion injury.

Migration capacity of human umbilical cord mesenchymal stem cells towards glioma in vivo

High-grade glioma is the most common malignant primary brain tumor in adults. The poor prognosis of glioma, combined with a resistance tQ currently available treatments, necessitates the develop- ment of more effective tumor-selective therapies. Stem cell-based therapies are emerging as novel cell-based delivery vehicle for therapeutic agents. In the present study, we successfully isolated human umbilical cord mesenchymal stem cells by expiant culture. The human umbilical cord mes- enchymal stem cells were adherent to plastic surfaces, expressed specific surface phenotypes of mesenchymal stem cells as demonstrated by flow cytometry, and possessed multi-differentiation potentials in permissive induction media in vitro. Furthermore, human umbilical cord mesenchymal stem cells demonstrated excellent glioma-specific targeting capacity in established rat glioma models after intratumoral injection or contralateral ventricular administration in vivo. The excellent glioma-specific targeting ability and extensive intratumoral distribution of human umbilical cord mesenchymal stem cells indicate that they may serve as a novel cellular vehicle for delivering therapeutic molecules in glioma therapy.

Noggin versus basic fibroblast growth factor on the differentiation of human embryonic stem cells

The difference between Noggin and basic fibroblast growth factor for the neural precursor differen- tiation from human embryonic stem cells has not been studied. In this study, 100 tJg/L Noggin or 20 IJg/L basic fibroblast growth factor in serum-free neural induction medium was used to differen- tiate human embryonic stem cells H14 into neural precursors using monolayer differentiation. Two weeks after induction, significantly higher numbers of neural rosettes formed in the Noggin-induced group than the basic fibroblast growth factor-induced group, as detected by phase contrast micro- scope. Immunofluorescence staining revealed expression levels of Nestin, [3-111 Tubulin and Sox-1 were higher in the induced cells and reverse-transcription PCR showed induced cells expressed Nestin, Sox-1 and Neurofilament mRNA. Protein and mRNA expression in the Noggin-induced group was increased compared with the basic fibroblast growth factor-induced group. Noggin has a greater effect than basic fibroblast growth factor on the induction of human embryonic stem cell differentiation into neural precursors by monolayer differentiation, as Noggin accelerates and in- creases the differentiation of neural precursors.

Targeting β-secretase with RNAi in neural stem cells for Alzheimer's disease therapy

There are several major pathological changes in Alzheimer＇s disease, including apoptosis of cho- linergic neurons, overactivity or overexpression of 13-site amyloid precursor protein cleaving enzyme 1 （BACE1） and inflammation. In this study, we synthesized a 19-nt oligonucleotide targeting BACE1, the key enzyme in amyloid beta protein （AI3） production, and introduced it into the pSilenCircle vector to construct a short hairpin （shRNA） expression plasmid against the BACE1 gene. We transfected this vector into C17.2 neural stem cells and primary neural stem cells, resulting in downregulation of the BACE1 gene, which in turn induced a considerable reduction in reducing AI3 protein production. We anticipate that this technique combining cell transplantation and gene ther- apy will open up novel therapeutic avenues for Alzheimer＇s disease, particularly because it can be used to simultaneously target several pathogenetic changes in the disease.

Are human dental papilla-derived stem cell and human brain-derived neural stem cell transplantations suitable for treatment of Parkinson’s disease?

Transplantation of neural stem cells has been reported as a possible approach for replacing impaired dopaminergic neurons. In this study, we tested the efficacy of early-stage human dental papilla-derived stem cells and human brain-derived neural stem cells in rat models of 6-hydroxydopamine-induced Parkinson＇s disease. Rats received a unilateral injection of 6-hydroxydopamine into right medial forebrain bundle, followed 3 weeks later by injections of PBS, early-stage human dental papilla-derived stem cells, or human brain-derived neural stem cells into the ipsilateral striatum. All of the rats in the human dental papilla-derived stem cell group died from tumor formation at around 2 weeks following cell transplantation. Postmortem examinations revealed homogeneous malignant tumors in the striatum of the human dental papilla-derived stem cell group. Stepping tests revealed that human brain-derived neural stem cell transplantation did not improve motor dysfunction. In apomorphine-induced rotation tests, neither the human brain-derived neural stem cell group nor the control groups （PBS injection） demonstrated significant changes. Glucose metabolism in the lesioned side of striatum was reduced by human brain-derived neural stem cell transplantation. [18F]-FP-CIT PET scans in the striatum did not demonstrate a significant increase in the human brain-derived neural stem cell group. Tyrosine hydroxylase （dopaminergic neuronal marker） staining and G protein-activated inward rectifier potassium channel 2 （A9 dopaminergic neuronal marker） were positive in the lesioned side of striatum in the human brain-derived neural stem cell group. The use of early-stage human dental papilla-derived stern cells confirmed its tendency to form tumors. Human brain-derived neural stem cells could be partially differentiated into dopaminergic neurons, but they did not secrete dopamine.

A ginkgo biloba extract promotes proliferation of endogenous neural stem cells in vascular dementia rats

The ginkgo biloba extract EGb761 improves memory loss and cognitive impairments in patients with senile dementia. It also promotes proliferation of neural stem cells in the subventricular zone in Parkinson＇s disease model mice and in the hippocampal zone of young epileptic rats. However, it remains unclear whether EGb761 enhances proliferation of endogenous neural stem cells in the brain of rats with vascular dementia. In this study, a vascular dementia model was established by repeatedly clipping and reperfusing the bilateral common carotid arteries of rats in combination with an intraperitoneal injection of a sodium nitroprusside solution. Seven days after establishing the model, rats were intragastrically given EGb761 at 50 mg/kg per day. Learning and memory abilities were assessed using the Morris water maze and proliferation of endogenous neural stem cells in the subventricular zone and dentate gyrus were labeled by 5-bromo-2-deoxyuridine immunofluorescence in all rats at 15 days, and 1, 2, and 4 months after model establishment. The escape latencies in Morris water maze tests of rats with vascular dementia after EGb761 treatment were significantly shorter than the model group. Immunofluorescence staining showed that the number and proliferation of 5-bromo-2-deoxyuridine-positive cells in the subventricular zone and dentate gyrus of the EGb761-treated group were significantly higher than in the model group. These experimental findings suggest that EGb761 enhances proliferation of neural stem cells in the subventricular zone and dentate gyrus, and significantly improves learning and memory in rats with vascular dementia.

Hyperbaric oxygen treatment promotes neural stem cell proliferation in the subventricular zone of neonatal rats with hypoxic-ischemic brain damage

Hyperbaric oxygen therapy for the treatment of neonatal hypoxic-ischemic brain damage has been used clinically for many years, but its effectiveness remains controversial. In addition, the mechanism of this potential neuroprotective effect remains unclear. This study aimed to investigate the influence of hyperbaric oxygen on the proliferation of neural stem cells in the subventricular zone of neonatal Sprague-Dawley rats （7 days old） subjected to hypoxic-ischemic brain damage. Six hours after modeling, rats were treated with hyperbaric oxygen once daily for 7 days. Immunohistochemistry revealed that the number of 5-bromo-2＇-deoxyuridine positive and nestin positive cells in the subventricular zone of neonatal rats increased at day 3 after hypoxic-ischemic brain damage and peaked at day 5. After hyperbaric oxygen treatment, the number of 5-bromo-2＇- deoxyuddine positive and nestin positive cells began to increase at day 1, and was significantly higher than that in normal rats and model rats until day 21. Hematoxylin-eosin staining showed that hyperbaric oxygen treatment could attenuate pathological changes to brain tissue in neonatal rats, and reduce the number of degenerating and necrotic nerve cells. Our experimental findings indicate that hyperbaric oxygen treatment enhances the proliferation of neural stem cells in the subventricular zone of neonatal rats with hypoxic-ischemic brain damage, and has therapeutic potential for promoting neurological recovery following brain injury.

Rat hair follicle stem cells differentiate and promote recovery following spinal cord injury

Emerging studies of treating spinal cord injury （SCI） with adult stem cells led us to evaluate the effects of transplantation of hair follicle stem cells in rats with a compression-induced spinal cord lesion. Here, we proposed a hypothesis that rat hair follicle stem cell transplantation can promote the recovery of injured spinal cord. Compression-induced spinal cord injury was induced in Wistar rats in this study. The bulge area of the rat vibdssa follicles was isolated, cultivated and characterized with nestin as a stem cell marker. 5-Bromo-2＇-deoxyuridine （BrdU） labeled bulge stem cells were transplanted into rats with spinal cord injury. Immunohistochemical staining results showed that some of the grafted cells could survive and differentiate into oligodendrocytes （receptor-interacting protein positive cells） and neuronal-like cells （~lll-tubulin positive cells） at 3 weeks after transplantation. In addition, recovery of hind limb locomotor function in spinal cord injury rats at 8 weeks following cell transplantation was assessed using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale. The results demon- strate that the grafted hair follicle stem cells can survive for a long time period in vivo and differentiate into neuronal- and glial-like cells. These results suggest that hair follicle stem cells can promote the recovery of spinal cord injury.

Differentiation of neuron-like cells from mouse parthenogenetic embryonic stem cells

Parthenogenetic embryonic stem cells have pluripotent differentiation potentials, akin to fertilized embryo-derived embryonic stem cells. The aim of this study was to compare the neuronal differentiation potential of parthenogenetic and fertilized embryo-derived embryonic stem cells. Before differentiation, karyotype analysis was performed, with normal karyotypes detected in both parthenogenetic and fertilized embryo-derived embryonic stem cells. Sex chromosomes were identified as XX. Immunocytochemistry and quantitative real-time PCR detected high expression of the pluripotent gene, Oct4, at both the mRNA and protein levels, indicating pluripotent differentiation potential of the two embryonic stem cell subtypes. Embryonic stern cells were induced with retinoic acid to form embryoid bodies, and then dispersed into single cells. Single cells were differentiated in N2 differentiation medium for 9 days. Immunocytochemistry showed parthenogenetic and fertilized embryo-derived embryonic stem cells both express the neuronal cell markers nestin, ~lll-tubulin and myelin basic protein. Quantitative real-time PCR found expression of neuregenesis related genes （Sox-1, Nestin, GABA, Pax6, Zic5 and Pitxl） in both types of embryonic stem cells, and Oct4 expression was significantly decreased. Nestin and Pax6 expression in parthenogenetic embryonic stem cells was significantly higher than that in fertilized embryo-derived embryonic stem cells. Thus, our experimental findings indicate that parthenogenetic embryonic stem cells have stronger neuronal differentiation potential than fertilized embryo-derived embryonic stem cells.

Stem cell properties and neural differentiation of sheep amniotic epithelial cells

This study was designed to verify the stem cell properties of sheep amniotic epithelial cells and their capacity for neural differentiation. Immunofluorescence microscopy and reverse transcription-PCR revealed that the sheep amniotic epithelial cells were positive for the embryonic stem cell marker proteins SSEA-1, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81, and the totipotency-associated genes Oct-4, Sox-2 and Rex-1, but negative for Nanog. Amniotic epithelial cells expressed β-Ⅲ-tubulin, glial fibrillary acidic protein, nestin and microtubule-associated protein-2 at 28 days after induction with serum-free neurobasal-A medium containing B-27. Thus, sheep amniotic epithelial cells could differentiate into neurons expressing β-Ⅲ-tubulin and microtubule-associated protein-2, and glial-like cells expressing glial fibrillary acidic protein, under specific conditions.

再生障碍性贫血患儿骨髓间充质干细胞体外造血支持作用的研究

目的骨髓间充质干细胞(mesenchymal stem cell,MSC)具有造血支持作用,再生障碍性贫血(aplastic anemia,AA)的发病机制涉及到造血微环境的异常,将两方面联系起来,体外研究再障患儿骨髓MSC的造血支持作用与再障的造血微环境异常的关系。方法采集24例再障患儿和19例对照儿童的骨髓标本,分离、培养和扩增MSC;观察细胞形态及骨髓MSC成纤维细胞集落形成单位(CFU-F)计数分析;应用MTT法检测骨髓MSC粘附造血细胞的能力;应用ELISA检测骨髓MSC分泌干细胞生长因子(SCF)的浓度;对骨髓MSC进行贴壁培养,接种骨髓单个核细胞,计数扩增细胞数和红系爆式集落生成单位(BFU-E),粒细胞巨噬细胞集落生成单位(CFU-GM),混合细胞集落生成单位(CFU-GMME)。结果①再障患儿骨髓MSC传代时间延长,CFU-F计数15.70±5.78显著低于对照组21.73±5.74,P<0.05;②再障患儿骨髓MSC培养上清中SCF的浓度30.69±16.82 pg/mL显著低于对照组50.74±14.83 pg/mL,P<0.01;③再障患儿骨髓MSC支持下的单个核细胞(MNC)细胞扩增总数和红系爆式集落生成单位(BFU-E),粒细胞巨噬细胞集落生成单位(CFU-GM),混合细胞集落生成单位(CFU-GMME)计数显著低于对照组,P<0.01。结论再障患儿骨髓MSC体外造血支持作用较对照儿童骨髓MSC显著降低,其发生机制可能与再障患儿骨髓MSC增殖能力减低及分泌SCF减少有关。

冻存前后骨髓间充质干细胞的生物学特性和支持造血的研究

为了了解冻存复苏过程对骨髓间充质干细胞(mesenchymalstemcell,MSC)生物学特性和支持造血能力的影响,采用常规方法分离培养骨髓MSC,将传代后的细胞用含10%二甲亚砜、40%胎牛血清的IMDM细胞冻存液保存在-196℃液氮中,观察短期(4周)和中期(9-15月)复苏后MSC的活性、免疫表型、多向分化能力和支持造血的能力,并同冻存前的MSC进行比较。结果表明:中短期冻存后的MSC的细胞活性分别为(90士3.75)%和(93士2.51)%;冻存后细胞的增殖能力、免疫表型、体外分化为脂肪和骨细胞的能力、支持集落(CFU-GM,CFU-E,CFU-GEMM)的生长作用和冻存前MSC相似。结论:骨髓MSC在液氮中短期和中期保存后,细胞活性略有下降,但是并不影响MSC的增殖、分化和支持造血能力。

运动疗法联合心理支持护理方法对减少造血干细胞移植患者并发症的效果观察

目的探讨运动疗法联合心理支持护理在临床中减少造血干细胞移植患者并发症的实际效果。方法选择2014年12月-2015年12月期间在新疆医科大学第一附属医院血液病中心一病区住院并行造血干细胞移植的84例患者,按照随机原则平均分为对照组(n=42)和观察组(n=42)2组,其中对照组给予一般护理措施,而观察组患者采取运动疗法联合心理护理进行护理干预,统计2组患者移植后3个月内的并发症发生率情况,并对2组患者的护理后舒适度、护理满意度进行分析。结果观察组患者在移植后3个月后各种并发症发生率相较对照组明显较低(P<0.05);观察组患者在各个方面的舒适度评分较对照组均明显升高(P<0.05);与此同时对照组患者护理后满意度为66.67%(28/42),观察组患者对护理工作满意度为95.24%(40/42),差异有统计学意义(P<0.05)。结论对行造血干细胞移植的患者,在治疗期间给予运动疗法联合心理支持疗法,能够降低相关并发症的发生率,提高患者对护理工作满意度,改善患者的负性情绪,值得临床推广。

大剂量化疗联合应用G-CSF治疗难治或复发性非霍奇金淋巴瘤的临床观察

目的:观察大剂量化疗联合应用粒细胞集落刺激因子在没有干细胞支持情况下,治疗难治或复发性非霍奇金淋巴瘤的疗效和不良反应。方法:采用大剂量化疗。MIE方案:异环磷酰胺1500mg/m2,iv,d1～6;美斯纳800mg/次,于异环磷酰胺后0、4、8小时,iv,并同时水化;足叶乙甙250mg/m2,iv,d1～6;粒细胞集落刺激因子5～10μg·kg-1·d-1,于末次化疗结束后24小时开始应用,至白细胞达2.0×109/L持续3天停用,4周重复下1个疗程。17例患者共接受化疗24个疗程。结果:大剂量化疗总有效率76.5%(13/17),其中6例(35.3%)获完全缓解,7例(41.2%)获部分缓解,稳定1例(5.9%),无效和恶化2例(11.8%),1例(5.9%)于大剂量化疗后第7天死于颅内出血。大剂量化疗主要不良反应为骨髓抑制,白细胞和血小板降到最低的中位时间分别为6天和5天,其恢复时间分别为10天和12天;13例(76.5%)为发热性粒细胞减少,中位时间为6天,应用抗生素的中位时间为7天,应用粒细胞集落刺激因子的中位时间为7天。结论:在无干细胞支持的情况下,采用大剂量化疗辅以粒细胞集落刺激因子支持是治疗难治或复发性非霍奇金淋巴瘤的有效措施,具有疗效高,早期死亡率低,不良反应能够耐受,无需全环境保护,费用较低的特点,是值得临床推广的治疗模式。

基于支持向量机和聚类分析理论的钻具失效分析方法

针对钻具失效影响因素比较复杂的问题,建立了基于支持向量机和聚类分析理论的钻具失效原因分析模型。应用该模型可收集钻具失效样本数据,并对数据进行机器学习及优化,得到最佳的内部结构,从而可以计算和分析出钻具失效的原因。对大庆油田某区块的钻具失效数据进行了处理和分析,确定了该区块钻具发生失效的根本原因,并且有针对性地提出了6点预防钻具失效措施。通过计算证明,这种新模型的计算和分析结果真实、可靠。

人骨髓基质干细胞克隆对脐血造血干细胞体外扩增作用的研究

探讨人骨髓基质干细胞的克隆化培养及其对体外造血干细胞扩增的影响。方法 :取正常肋骨分离骨髓 ,制备单个核细胞贴壁培养 ,约 5d后取集落样生长的梭形细胞扩增培养、传代。将分选的脐血造血干 /祖细胞接种到克隆培养的人骨髓基质干细胞及其他培养条件液上 ,比较不同培养条件及不同代次骨髓基质干细胞对造血干 /祖细胞扩增能力及集落形成能力的影响。结果 :人骨髓基质干细胞能扩增达 2 0代以上 ,经流式细胞仪检测证实为基质干细胞 ,单纯细胞因子组和细胞因子加基质干细胞组能有效扩增造血细胞 ,而后者有维持长期造血的作用。结论 :该克隆培养方法能有效扩增骨髓基质干细胞 ,培养的细胞有体外支持长期造血的作用。