BM-MSCs延缓CD8^(+)初始T细胞衰老

目的验证骨髓间充质干细胞(BM-MSCs)缓解免疫衰老的作用,探究其衰老改善的主要免疫细胞群体。方法分离获得小鼠脾淋巴细胞,刺激增殖7d构建复制性衰老细胞模型。利用流式细胞测量术检测年轻对照组、复制性衰老对照组和BM-MSCs共培养组T细胞亚群衰老标志物p16ink4a(p16)和p21cip1(p21)的表达水平。结果T淋巴细胞复制性衰老模型中观察到持续增殖后CD8^(+)T细胞较CD4^(+)T细胞衰老显著,在CD8^(+)T细胞的初始细胞、效应细胞亚群中,效应细胞衰老最显著;BM-MSCs共培养对衰老的效应细胞没有明显影响,主要通过延缓初始T细胞的衰老,达到缓解CD8^(+)T细胞衰老的作用(P<0.01,P<0.001)。结论与BM-MSCs共培养可以缓解T细胞的复制性衰老表型,对CD8^(+)T细胞的抗衰作用更显著,主要通过抑制初始T细胞的衰老实现。

Repair of peripheral nerve defects with chemically extracted acellular nerve allografts loaded with neurotrophic factors-transfected bone marrow mesenchymal stem cells

Chemically extracted acellular nerve allografts loaded with brain-derived neurotrophic fac- tor-transfected or ciliary neurotrophic factor-transfected bone marrow mesenchymal stem cells have been shown to repair sciatic nerve injury better than chemically extracted acellular nerve allografts alone, or chemically extracted acellular nerve allografts loaded with bone marrow mesenchymal stem cells. We hypothesized that these allografts compounded with both brain-derived neurotrophic factor- and ciliary neurotrophic factor-transfected bone marrow mesenchymal stem cells may demonstrate even better effects in the repair of peripheral nerve injury. We cultured bone marrow mesenchymal stem cells expressing brain-derived neuro- trophic factor and/or ciliary neurotrophic factor and used them to treat sciatic nerve injury in rats. We observed an increase in sciatic functional index, triceps wet weight recovery rate, myelin thickness, number of myelinated nerve fibers, amplitude of motor-evoked potentials and nerve conduction velocity, and a shortened latency of motor-evoked potentials when al- lografts loaded with both neurotrophic factors were used, compared with allografts loaded with just one factor. Thus, the combination of both brain-derived neurotrophic factor and cili- ary neurotrophic factor-transfected bone marrow mesenchymal stem cells can greatly improve nerve injury.

The genomic landscapes of histone H3-Lys9 modifications of gene promoter regions and expression profiles in human bone marrow mesenchymal stem cells

Mesenchymal stem cells （MSCs） of nonembryonic origins possess the proliferation and multi-lineage differentiation potentials. It has been established that epigenetic mechanisms could be critical for determining the fate of stem cells, and MSCs derived from different origins exhibited different expression profiles individually to a certain extent. In this study, ChiP-on-chip was used to generate genome-wide histone H3-Lys9 acetylation and dimethylation profiles at gene promoters in human bone marrow MSCs. We showed that modifications of histone H3-Lys9 at gene promoters correlated well with mRNA expression in human bone marrow MSCs. Functional analysis revealed that many key cellular pathways in human bone marrow MSC self-renewal, such as the canonical signaling pathways, cell cycle pathways and cytokine related pathways may be regulated by H3-Lys9 modifications. These data suggest that gene activation and silencing affected by H3-Lys9 acetylation and dimethylation, respectively, may be essential to the maintenance of human bone marrow MSC self-renewal and multi-potency.

Bone marrow-derived mesenchymal stem cells increase dopamine synthesis in the injured striatum

Previous studies showed that tyrosine hydroxylase or neurturin gene-modified cells transplanted into rats with Parkinson＇s disease significantly improved behavior and increased striatal dopamine content. In the present study, we transplanted tyrosine hydroxylase and neurturin gene-modified bone marrow-derived mesenchymal stem cells into the damaged striatum of Parkinson＇s disease model rats. Several weeks after cell transplantation, in addition to an improvement of motor function tyrosine hydroxylase and neurturin proteins were up-regulated in the injured striatum, and importantly, levels of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid increased significantly. Furthermore, the density of the D2 dopamine receptor in the postsynaptic membranes of dopaminergic neurons was decreased. These results indicate that transplantation of tyrosine hydroxylase and neurturin gene-modified bone marrow-derived mesenchymal stem cells increases dopamine synthesis and significantly improves the behavior of rats with Parkinson＇s disease.

Mesenchymal Stromal Cells Derived from Human Embryonic Stem Cells, Fetal Limb and Bone Marrow Share a Common Phenotype but Are Transcriptionally and Biologically Different

Mesenchymal stromal cells (MSCs) can be obtained from several sources and the significant differences in their properties make it crucial to investigate the differentiation potential of MSCs from different sources to determine the optimal source of MSCs. We investigated if this biological heterogeneity in MSCs from different sources results in different mechanisms for their differentiation. In this study, we compared the gene expression patterns of phenotypically defined MSCs derived from three ontogenically different sources: Embryonic stem cells (hES-MSCs), Fetal limb (Flb-MSCs) and Bone Marrow (BM-MSCs). Differentially expressed genes between differentiated cells and undifferentiated controls were compared across the three MSC sources. We found minimal overlap (5% - 16%) in differentially expressed gene sets among the three sources. Flb-MSCs were similar to BM-MSCs based on differential gene expression patterns. Pathway analysis of the differentially expressed genes using Ingenuity Pathway Analysis (IPA) revealed a large variation in the canonical pathways leading to MSC differentiation. The similar canonical pathways among the three sources were lineage specific. The Flb-MSCs showed maximum overlap of canonical pathways with the BM-MSCs, indicating that the Flb-MSCs are an intermediate source between the less specialised hES-MSC source and the more specialised BM-MSC source. The source specific pathways prove that MSCs from the three ontogenically different sources use different biological pathways to obtain similar differentiation outcomes. Thus our study advocates the understanding of biological pathways to obtain optimal sources of MSCs for various clinical applications.

Neuronal-like differentiation of bone marrow-derived mesenchymal stem cells induced by striatal extracts from a rat model of Parkinson's disease

A rat model of Parkinson＇s disease was established by 6-hydroxydopamine injection into the medial forebrain bundle. Bone marrow-derived mesenchymal stem cells （BMSCs） were isolated from the femur and tibia, and were co-cultured with 10% and 60% lesioned or intact striatal extracts. The results showed that when exposed to lesioned striatal extracts, BMSCs developed bipolar or multi-polar morphologies, and there was an increase in the percentage of cells that expressed glial fibrillary acidic protein （GFAP）, nestin and neuron-specific enolase （NSE）. Moreover, the percentage of NSE-positive cells increased with increasing concentrations of lesioned striatal extracts. However, intact striatal extracts only increased the percentage of GFAP-positive cells. The findings suggest that striatal extracts from Parkinson＇s disease rats induce BMSCs to differentiate into neuronal-like cells in vitro.

Hypoxic Preconditioning Improved Neuroprotective Effect of Bone Marrow-Mesenchymal Stem Cells Transplantation in Acute Glaucoma Models

This study explored the novel strategy of hypoxic preconditioning of Bone Marrow Mesenchymal Stem Cells (BM-MSCs) before intra vitreal transplantation to improve neuroprotective effects of Retinal Ganglion Cells (RGCs) in Acute Glaucoma Models. The methods of this research were isolated mesenchymal stem cells from the bone marrow of adult wild-type Sprague-Dawley (SD) rats. BM-MSCs were cultured under normoxic or hypoxic (1% oxygen for 24 hours) conditions. Normoxic or hypoxic BM-MSCs were transplanted intravitreally 1 week after ocular hypertension induction by acutely increasing IOP to 100 - 120 mmHg for 60 minutes. Rats were killed 4 weeks after transplanted. Apoptosis was examined by tunnel assay and expression Brn3b (Brn3b = RGCs marker) by immunohistochemical analysis of the retina. Results showed that transplantation of hypoxic preconditioning BM-MSCs in acute glaucoma models resulted in a significant apoptosis decreasing (p < 0.05) and an significant increasing in RGCs (p < 0.05), as well as enhanced mor-phologic and functional benefits of stem cell therapy versus normoxic BM-MSCs transplantation. Conclusions: Hypoxic preconditioning enhances the capacity of BM-MSCs transplantation to improve neuroprotective effects of RGCs in Acute Glaucoma Models.

缺氧预处理MSCs移植对脑缺血再灌注损伤大鼠SDF-1/CXCR4表达的影响及清热化瘀方的干预作用

目的观察缺氧预处理骨髓间充质干细胞(MSCs)移植对脑缺血再灌注损伤大鼠SDF-1/CXCR4 m RNA和蛋白表达的影响及清热化瘀方的干预作用。方法采用线栓法制备局灶性脑缺血大鼠(MCAO)模型,将216只SD大鼠随机分为6组:假手术组(SO)、模型组(MCAO)、MSCs移植对照组(N-MSCs)、经HP处理后的MSCs移植组(HP-MSCs)、MSCs移植联合清热化瘀方组(MSCs+QRHY)、HP-MSCs移植联合清热化瘀方组(HP+QRHY)。每组大鼠36只,每组根据取材时间点7,14,28 d又可分为每组3个亚组,每个亚组12只大鼠。采用q RT-PCR和Western blot观察3个时间点SDF-1/CXCR4 m RNA及其蛋白的表达变化,并以TUNEL法检测神经细胞凋亡。结果各组缺血半暗带SDF-1/CXCR4 m RNA及其蛋白的表达均于7d达到高峰,14,28 d表达逐渐下降。其中7,14 d同一时间点组间比较,HP-MSCs组、MSCs+QRHY组及HP+QRHY组二者的表达均明显优于N-MSCs组(P<0.01,P<0.05),而以HP+QRHY组增高最为明显(P<0.05,P<0.01),28 d后,各移植组的表达趋势趋同,但仍高于模型组(P<0.05)。结论缺氧预处理MSCs移植能够显著提高脑缺血再灌注损伤大鼠SDF-1/CXCR4的表达,清热化瘀方能够进一步上调SDF/1CXCR4的表达,减少细胞凋亡。

过表达miR-217调控EZH2促进骨质疏松模型小鼠BM-MSCs成骨分化

目的探究微小RNA-217(miR-217)对骨质疏松症(OP)模型小鼠骨髓间充质干细胞(BM-MSCs)成骨分化的影响及其可能调控机制。方法将小鼠分为OP组、假手术(sham)组,各12只,均进行了双侧卵巢切除术。将OP小鼠BM-MSCs分为对照组、miR-NC组、miR-217 mimics组、miR-217 mimics+pcDNA 3.1组、miR-217 mimics+pcDNA 3.1-EZH2(果蝇zeste基因增强子同源物2)组,分别不做转染、转染miR-NC、转染miR-217 mimics、转染miR-217 mimics及pcDNA 3.1、转染miR-217 mimics及pcDNA 3.1-EZH2,之后进行成骨诱导分化。RT-qPCR/Western blot检测miR-217及EZH2、OCN、Runx2、collagenⅠmRNA和蛋白表达情况;酶标仪检测各组BM-MSCs碱性磷酸酶(ALP)活性;利用茜素红S(ARS)染色测定法对各组BM-MSCs进行染色,观察染色情况;双荧光素酶报告基因验证miR-217与EZH2的靶向关系。结果OP组小鼠骨组织及BM-MSCs中miR-217表达水平低于sham组(P<0.05),EZH2 mRNA表达水平高于sham组(P<0.05)。miR-217 mimics组BM-MSCs中miR-217表达水平,OCN、Runx2、collagenⅠmRNA和蛋白表达水平,ALP活性高于对照组和miR-NC组(P<0.05),EZH2 mRNA及蛋白表达水平低于对照组和miR-NC组(P<0.05),ARS染色程度重于对照组和miR-NC组。miR-217 mimics+pcDNA 3.1-EZH2组BM-MSCs中EZH2 mRNA及蛋白表达水平高于miR-217 mimics组、miR-217 mimics+pcDNA 3.1组(P<0.05),OCN、Runx2、collagenⅠmRNA和蛋白表达水平,ALP活性低于miR-217 mimics组、miR-217 mimics+pcDNA 3.1组(P<0.05),ARS染色程度轻于miR-217 mimics组、miR-217 mimics+pcDNA 3.1组。miR-217与EZH2 mRNA 3′UTR区有结合位点,WT-EZH2+miR-217 mimics组荧光素酶相对活性低于WT-EZH2+miR-NC组(P<0.05)。结论过表达miR-217可通过靶向抑制EZH2表达,促进OP小鼠BM-MSCs成骨分化,为临床防治OP提供新策略。

HFOV 联合 MSCs 移植对急性肺损伤后肺纤维化的影响

目的：探讨高频振荡通气（HFOV）联合骨髓间充质干细胞（MSCs）对内毒素诱发急性肺损伤模型兔肺纤维化的影响。方法家兔34只，2只用于制备MSCs，剩余32只随机分为4组：肺损伤组、HFOV组、MSCs移植组和HFOV＋MSCs移植组，每组8只。全骨髓培养法体外培养兔MSCs，传至第3代备用。通过向气管内滴注内毒素建立急性肺损伤／急性呼吸窘迫综合征模型。分别在干预后2周时间点，采用酸解法测定肺组织羟脯氨酸含量；采用ELISA法检测各组血清和支气管肺泡灌洗液中转化生长因子-β（ TGF-β）及单核细胞趋化蛋白-1（ MCP-1）的表达；取右肺一叶标本，行病理学检查。结果 MSCs组中肺组织羟脯氨酸含量、血清及支气管肺泡灌洗液中TGF-β、MCP-1的表达水平，分别与肺损伤组比较差异有统计学意义（P＜0．05），而单一HFOV组与肺损伤组比较差异均无统计学意义（P＞0．05）；联合HFOV＋MSCs组中肺组织羟脯氨酸含量、血清及支气管肺泡灌洗液中 TGF -β、MCP -1的表达水平最低，分别与单一HFOV组和MSCs组比较差异均有统计学意义（P＜0．05）。肺组织病理学提示，MSCs组的纤维化程度减轻，HFOV＋MSCs组程度最轻。结论 HFOV联合MSCs可减少急性肺损伤兔肺组织羟脯氨酸含量，降低TGF-β、MCP-1的表达，减轻急性肺损伤后纤维化程度，优于单一方法，具有协同作用。

与软骨细胞共培养促进BMSCs分化为软骨细胞

目的:将兔骨髓间充质干细胞(bone marrow mesenchymal stem cell,BMSC)和关节软骨细胞在离心管内聚集共培养获取软骨细胞,并与全软骨细胞比较离心管内培养的差异。方法:取兔骨髓和软骨,分离BMSC和软骨细胞分别进行培养,用阿利新蓝染色、番红花O-亮绿染色、Ⅱ型胶原免疫组化染色鉴定软骨细胞;用免疫荧光法检测CD44、CD105、CD34、CD45的表达鉴定BMSC。取3×10~7/m L第3代BMSC和1×10~7/m L原代软骨细胞按3∶1比例混于离心管内,为共培养组;另将4×10~7/m L原代软骨细胞移入离心管内培养,作为软骨细胞组。培养4周,每周收集细胞上清液,检测细胞糖胺聚糖、Ⅱ型胶原含量。结果:软骨细胞组与共培养组在培养的1~4周中细胞大体形态、组织学变化无明显差别;两组细胞1~4周分泌糖胺聚糖比较差异无统计学意义(P>0.05),Ⅱ型胶原量在第1周时有差异,后3周时无统计学差异(P>0.05)。结论:BMSC和软骨细胞离心管内聚集共培养可诱导BMSC分化为软骨细胞,其数量和质量与单纯软骨细胞效果同等。

Similarities and differences between mesenchymal stem/progenitor cells derived from various human tissues

BACKGROUND Mesenchymal stromal/stem cells (MSCs) constitute a promising tool in regenerative medicine and can be isolated from different human tissues. However, their biological properties are still not fully characterized. Whereas MSCs from different tissue exhibit many common characteristics, their biological activity and some markers are different and depend on their tissue of origin. Understanding the factors that underlie MSC biology should constitute important points for consideration for researchers interested in clinical MSC application. AIM To characterize the biological activity of MSCs during longterm culture isolated from: bone marrow (BM-MSCs), adipose tissue (AT-MSCs), skeletal muscles (SMMSCs), and skin (SK-MSCs). METHODS MSCs were isolated from the tissues, cultured for 10 passages, and assessed for: phenotype with immunofluorescence and flow cytometry, multipotency with differentiation capacity for osteo-, chondro-, and adipogenesis, stemness markers with qPCR for mRNA for Sox2 and Oct4, and genetic stability for p53 and c-Myc;27 bioactive factors were screened using the multiplex ELISA array, and spontaneous fusion involving a co-culture of SM-MSCs with BM-MSCs or AT-MSCs stained with PKH26 (red) or PKH67 (green) was performed. RESULTS All MSCs showed the basic MSC phenotype;however, their expression decreased during the follow-up period, as confirmed by fluorescence intensity. The examined MSCs express CD146 marker associated with proangiogenic properties;however their expression decreased in AT-MSCs and SM-MSCs, but was maintained in BM-MSCs. In contrast, in SK-MSCs CD146 expression increased in late passages. All MSCs, except BM-MSCs, expressed PW1, a marker associated with differentiation capacity and apoptosis. BM-MSCs and AT-MSCs expressed stemness markers Sox2 and Oct4 in long-term culture. All MSCs showed a stable p53 and c-Myc expression. BM-MSCs and AT-MSCs maintained their differentiation capacity during the follow-up period. In contrast, SK-MSCs and SM-MSCs had a limited ability to differentiate into adipocytes. BM-MSCs and AT-MSCs revealed similarities in phenotype maintenance, capacity for multilineage differentiation, and secretion of bioactive factors. Because AT-MSCs fused with SM-MSCs as effectively as BM-MSCs, AT-MSCs may constitute an alternative source for BM-MSCs. CONCLUSION Long-term culture affects the biological activity of MSCs obtained from various tissues. The source of MSCs and number of passages are important considerations in regenerative medicine.

CNTF干扰对BMSCs动脉移植缺血再灌注损伤脊髓下游信号通路STAT3/Caspase-9的影响

目的探讨CNTF干扰对肾下腹主动脉移植骨髓间充质干细胞治疗SCIRI大鼠脊髓下游信号通路STAT3/Caspase-9及损伤脊髓功能恢复的影响.方法成年SD雌性大鼠随机分组.BBB评分、CSEP和MEP法检测大鼠行为和神经电生理;IHC检测缺血脊髓腰段CNTF的表达;Western Blot、RT-PCR分析缺血脊髓腰段STAT3、p-STAT3、CNTF、Caspase-9的表达.结果对照组、移植组和Anti-CNTF干扰组大鼠BBB评分在术后各时间点均显著低于假手术组(P<0.01),MEP、CSEP潜伏期亦延长(P<0.01)、波幅亦减小(P<0.01),对照组变化最明显,Anti-CNTF干扰组次之,移植组最弱,组间均差异有统计学意义(P<0.05).术后7d,脊髓CNTF免疫阳性产物在Anti-CNTF干扰组减少(P<0.05),在对照组和移植组均增加(P<0.05),且移植组高于对照组(P<0.05).术后7d,缺血节段脊髓内CNTF、STAT3和p-STAT3 m RNA和蛋白表达在Anti-CNTF干扰组减少(P<0.05),在对照组和移植组均增加(P<0.05),且移植组高于对照组(P<0.05);而Caspase-9基因和蛋白表达仅在移植组减少(P<0.05),在Anti-CNTF干扰组和对照组均增加(P<0.01),且Anti-CNTF干扰组增加更显著(P<0.05).术后14d,Anti-CNTF干扰组脊髓内CNTF、STAT3和p-STAT3 m RNA和蛋白表达明显高于假手术组和对照组(P<0.05),而Caspase-9的表达高于假手术组却低于对照组(P<0.05),各因子的表达较移植组差异无统计学意义(P>0.05).结论 BMSCs高表达CNTF介导下游STAT3/Caspase-9信号通路促进SCIRI大鼠后肢功能恢复,而CNTF干扰可以抑制STAT3/Caspase-9信号通路,不利于BMSCs移植对SCIRI大鼠后肢功能改善.

Trichostatin A and Shear Stress in Regulating Endothelium Differentiation of Bone Marrow Mesenchymal Stem Cells

Differentiation of bone marrow mesenchymal stem cells (MSCs) into endothelial cells (EC) is characterized by the expression of specific endothelial marker genes. Mechanical stimulations play potential effects in EC oriented differentiation of MSCs. However, molecular mechanisms of endothelial differentiation from MSCs have not been defined.Histone acetylations play important roles in regulating gene expression. Histone acetylation status is maintained by histone acetyltransferase (HAT) and histone deacetylases (HDACs). Our previous work described that VEGF and laminar shear stress (SS) work together in determining EC oriented differentiation of MSC. Trichostatin A (TSA) is one of the lustone deacetylase inhibitor. In this study, we found that both TSA and SS could induce EC oriented differentiation of MSCs. And TSA combined with SS showed more powerful influence on the EC oriented differentiation of MSCs.

骨髓基质细胞通过TSP-1/CD36通路对急性髓系白血病细胞影响的初步研究

目的:探讨骨髓基质细胞(bone marrow-derived mesenchymal stromal cells,BM-MSCs)对急性髓系白血病(acute myeloid leukemia,AML)细胞影响的作用机制。方法:构建MLL-AF9过表达诱导的AML小鼠模型,通过PCR比较AML小鼠和野生型小鼠(WT)BM-MSCs内TSP-1的表达差异。通过慢病毒载体使AML小鼠来源的BM-MSCs高表达TSP-1后,与AML细胞行transwell共培养,检测AML细胞表面TSP-1受体CD36及CD47的表达及AML细胞的生长情况。在共培养体系中加入CD36抑制剂N-油酰基硫代琥珀酰亚胺,检测AML细胞增殖、凋亡的变化。结果:AML小鼠BM-MSCs中TSP-1的表达低于对照组。过表达TSP-1的BM-MSCs与AML细胞行transwell共培养后AML细胞的生长受到抑制,且AML细胞表面的CD36受体表达升高,但CD47表达无明显差异。在共培养体系中加入CD36抑制剂N-油酰基硫代琥珀酰亚胺后,AML细胞增殖加快,凋亡减少。结论:TSP-1/CD36信号通路有望成为治疗AML的潜在靶点。

骨髓间充质干细胞在去卵巢大鼠骨质疏松发病机理中潜在的作用

为探讨去卵巢骨质疏松大鼠骨髓间充质干细胞(Bone m arrow m esenchym a l stem ce lls,M SC s)成纤维细胞集落生成单位(CFU-F s)、细胞周期、成骨分化能力和成脂分化能力的变化,选用3月龄和6月龄健康雌性SD大鼠行双侧卵巢切除术,建立骨质疏松动物模型,动物实验分为4组:(1)3月龄正常组(con tro l-3);(2)3月龄卵巢切除组(OVX-3);(3)6月龄正常组(con tro l-6);(4)6月龄卵巢切除组(OVX-6)。采用密度梯度离心方法分别获取各组M SC s,体外培养,选用第3~4代M SC s用于实验。倒置相差显微镜观察CFU-F s;流式细胞技术检测细胞周期、细胞增殖指数(pro liferation index,P I)和细胞凋亡指数(apoptotic index,A I))。加入成骨诱导剂,采用碱性磷酸酶活性蛋白检测法(IFCC推荐法)检测M SC s碱性磷酸酶(a lka line phosphatase,ALP)分泌量;采用同位素标记方法检测骨钙素(O steoca lc in,OCN)分泌量;茜素红染色观察钙结节形成。加入成脂诱导剂,油红O染色观察M SC s内脂滴形成;RT-PCR方法检测M SC s脂蛋白脂酶(lipoprote in lipase,LPL)mRNA的表达。结果表明:与相应对照组比较,OVX-3组和OVX-6组CFU-F s、P I值明显降低(P<0.05),A I值明显增加(P<0.05);OVX-6组CFU-F s、P I值的降低和A I值的增加都明显大于OVX-3组(P<0.05)。成骨诱导表明:与相应对照组比较,OVX-3组和OVX-6组ALP、BGP分泌量以及钙结节形成的数量均明显降低(P<0.05),OVX-6组的降低最为明显。成脂诱导表明:与相应对照组比较,OVX-3组和OVX-6组,LPL mRNA的表达量明显增加(P<0.05),OVX-6组LPL mRNA的表达量的增加明显高于其他各组(P<0.05)。结论:去卵巢骨质疏松大鼠M SC s增殖能力明显下降,向成骨细胞分化能力下降,向脂肪细胞分化能力增强,其中6OVX组M SC s的变化最明显。提示:去卵巢骨质疏松大鼠M SC s向成骨细胞分化能力的降低和向脂肪细胞分化能力的增强,可能与绝经后骨质疏松症的发生相关。

骨髓间充质干细胞向神经元的诱导分化

目的 :探讨大鼠骨髓间充质干细胞 ( rat mesenchymal stem cells,r MSCs)体外诱导分化成神经元的能力。方法 :用 0 .2 5、0 .5、1 .0 mmol· L-1IBMX诱导传代的 r MSCs,待细胞分化后进行形态学观察 ,并用免疫细胞化学方法进行细胞鉴定。结果 :0 .5 mmol· L-1IBMX诱导细胞效果最好 ,2 d即可见有神经元样细胞出现 ,6d神经元样细胞占细胞总数的 ( 2 3.2± 2 .3) %,NSE染色阳性。未分化细胞表达 nestin,诱导 3d,阳性细胞增多 ,6d减少。结论 :体外 r MSC能扩增、传代 。

骨髓间质干细胞体外定向诱导分化为软骨细胞的实验研究

目的:探讨分离骨髓间充质干细胞(MSCs)并诱导其向软骨细胞转化的体外培养方法,为软骨组织工程的种子细胞来源提供实验依据。方法:抽取兔髂骨骨髓液,经梯度离心法和贴壁法进行体外培养,贴壁细胞传代,取第3代细胞在培养基中添加软骨分化诱导剂[转化生长因子(TGFβ2)10ng/ml、地塞米松10-7mol/L、维生素C50μmol/L],经7、14、21d诱导培养后,倒置显微镜观察细胞形态,免疫组织化学染色检测软骨特异性Ⅱ型胶原表达。将诱导细胞与软骨支架材料——聚磷酸钙纤维/左旋聚乳酸(CPP/PLLA)复合,1周后终止培养,扫描电镜观察细胞黏附情况。结果:诱导后细胞体外扩增能力显著降低,细胞形态由成纤维样梭形向多角形、多边形或类圆形转变,诱导21d后细胞形态变化最为显著,Ⅱ型胶原免疫组化染色深而均匀。诱导后的MSCs可在支架材料内良好黏附生长。结论:体外培养的MSCs可定向诱导分化为软骨细胞,分泌软骨细胞特异性基质,可用作软骨组织工程的种子细胞。

人骨髓间充质干细胞的分离培养及表型分析

目的体外分离培养人骨髓间充质干细胞(MSCs)并研究其生物学特性,为进一步实验研究打下基础。方法通过密度梯度离心法及贴壁培养分离纯化人骨髓中的单个核细胞、体外培养传代、倒置相差显微镜观察细胞生长情况、瑞氏染色及透射电镜观察细胞形态及结构、绘制生长曲线、流式细胞仪检测细胞表面标记及增殖周期、免疫细胞化学及细胞化学染色对分离培养细胞进行鉴定。结果原代和传代培养的细胞以成纤维样为主,有较强的生长增殖能力;流式细胞仪检测细胞表面标记:CD29、CD105阳性,CD34阴性;细胞周期分析:90%以上的细胞处于G0/G1期;细胞CD106、纤维连接蛋白表达阳性,CD45、CD14及层连蛋白、胶原蛋白Ⅱ表达阴性,细胞糖原(PAS)染色强阳性,细胞碱性磷酸酶(ALP)染色阴性。表明细胞不是造血细胞且未向成纤维细胞、成骨细胞、软骨细胞分化,而是处于未分化阶段的间充质干细胞。结论通过密度梯度离心法及贴壁传代培养可以分离纯化MSCs以满足下一步实验研究,该细胞具有特殊的生物学特性。

力学应变对大鼠骨髓间充质干细胞增殖和成骨分化能力的影响

探讨周期性双轴力学应变对大鼠骨髓间充质干细胞(M esenchym a l stem ce lls,M SC s)增殖和成骨分化能力的影响。选用9月龄健康SD雌性大鼠,分离股骨、胫骨提取骨髓,采用密度梯度离心法分离M SC s。体外培养M SC s传至第3代,以1×105细胞浓度接种于双轴力学应变系统,选取4 000μstra in,频率为1hz的力学应变对M SC s加载。每天加载3次,每次2 h,间隔2 h。观察力学应变作用后1 d、3 d,M SC s增殖和成骨分化能力的变化,并与相应未加力学应变对照组比较。结果表明:(1)力学应变可增高M SC s的碱性磷酸酶(ALP)和骨桥蛋白(OPN)表达量;力学应变作用3 d后M SC s的ALP和OPN表达量明显高于力学应变作用1 d。I型胶原(COL I)仅在力学应变作用3 d增高;骨钙素(OCN)在各组无明显变化。(2)力学应变可促进M SC s增殖,但力学应变作用1 d和3 d对M SC s增殖的作用无明显差异。上述结果提示:力学应变可以促进M SC s的增殖和成骨分化能力。