腺病毒介导的CTLA-4Ig基因转染人骨髓间充质干细胞成骨特性研究

目的 通过腺病毒介导CTLA-4Ig基因转染人骨髓间充质干细胞(human marrow mesenchymal stem cells, hMSCs),观察被修饰细胞CTLA-4Ig蛋白表达情况,以及基因修饰对hMSCs诱导成骨特性的影响.方法 采用荧光显微镜观察腺病毒介导CTLA-4Ig基因转染hMSCs的绿色荧光蛋白表达,流式细胞术检测确定转染率,观察对比转染前后细胞形态和细胞周期,用免疫细胞化学方法检测转染hMSCs的CTLA-4Ig蛋白表达,转染hMSCs成骨诱导培养3周后进行成骨特异性标记检测.结果 分离培养的hMSCs CD105表达阳性, CD34表达阴性.重组腺病毒介导的CTLA-4Ig基因转染hMSCs的转染率为81.14%, CTLA-4Ig基因转染hMSCs(CTLA-4Ig-hMSCs)的形态无明显变化,生长良好.免疫细胞化学结果显示,CTLA-4Ig-hMSCs的CTLA-4Ig蛋白表达阳性,诱导培养3周的CTLA-4Ig-hMSCs,碱性磷酸酶染色呈强阳性,免疫细胞化学检测骨钙素表达阳性,钙的四环素荧光标记法显示细胞间有钙的沉积.结论 腺病毒介导的CTLA-4Ig基因转染hMSCs能够分泌CTLA-4Ig蛋白,并保持了成骨分化潜能,可用于异基因hMSCs作为骨组织工程种子细胞的应用研究.     

骨碎补各种提取成分对人骨髓间充质干细胞的影响

目的初步探讨骨碎补水提液、醇提液以及骨碎补的有效成分柚皮甙对人骨髓间充质干细胞（human bone marrow mesenchymal stem cells，hMSCs）增殖、分化的影响。方法将骨碎补水提液、醇提液和骨碎补的有效成分柚皮甙与hMSCs共同体外培养，倒置显微镜观察描述细胞生长情况、CCK-8法检测每组药液对细胞的毒性和增殖作用、碱性磷酸酶（ALP）活性测定，图文报告分析系统检测Von Kossa染色的钙结节，统计学处理所得数据。结果与空白对照组比较，1mg／L骨碎补水提液、50μg／L骨碎补醇提液与50μg／L柚皮甙能促进hMSCs增加（P〈0．05），50μg／L骨碎补醇提液与50μg／L柚皮甙能促进其向成骨细胞分化（P〈0．05）。结论骨碎补水提液、醇提液与柚皮甙对hMSCs有保护作用并能分别促进其增殖、分化。     

应用hMSCs-脱钙骨复合物体内构建软骨组织的实验研究

目的 观察成软骨诱导后人骨髓间充质干细胞和脱钙骨复合物在裸鼠皮下组织形成情况。方法 从志愿者髂前上嵴处抽取骨髓,得到骨髓间充质干细胞,将第1代的骨髓间充质干细胞密度调整到1.5×107/mL,均匀接种于脱钙骨,培养4 h后以含有TGF-β3(10 ng/mL)DMEM培养液的培养作为实验组,加10％FBS的DMEM为对照组Ⅰ,空白材料为对照组Ⅱ,体外培养6 d,嘲植到裸鼠皮下。回植前及回植后2、4、6、8、10周取材,石蜡切片进行Ⅰ、Ⅱ、Ⅲ型胶原的免疫组化、Masson’s、Alician Blue’s染色鉴定。结果 回植前及回植后各时间段,实验组免疫组化测到Ⅰ、Ⅱ、Ⅲ型胶原的表达,对照组未见Ⅱ型胶原表达;实验组Masson、Alician染色可见材料内的胶原分泌非常旺盛,有硫酸化酸性粘多糖沉积,对照组则表达量极少。结论 诱导后人骨髓间充质干细胞一脱钙骨复合物在裸鼠皮下能表达特异性软骨基质。     

骨碎补有效成分柚皮甙对人骨髓间充质干细胞的影响

目的探讨骨碎补的有效成分柚皮甙对人骨髓间充质干细胞(hMSCs)增殖、分化的影响。方法将骨碎补的有效成分柚皮甙以及成骨诱导液(地塞米松、维生素C、β-甘油磷酸钠)与hMSCs共同体外培养,用倒置显微镜观察细胞生长情况、CCK-8法检测细胞的毒性和增殖作用、碱性磷酸酶(ALP)活性测定、von kossa钙结节染色。结果50μg/L柚皮甙对细胞无毒性、能促进hMSCs增殖,碱性磷酸酶(ALP)活性、von kossa钙结节染色与空白对照组比较有明显差异(P<0.05)。结论柚皮甙对hMSCs有保护作用并能促进其增殖、分化。     

人骨髓间充质干细胞体外培养扩增及向心肌细胞诱导分化的实验研究

目的:培养人骨髓间充质干细胞(Human mesenchymal stem cell,hMSCs),探讨hMSCs体外向心肌细胞(Cardio-myocytes,CM)定向诱导分化的实验研究。方法:取人的骨髓血,用Percoll(1.073g/ml)密度梯度离心及贴壁筛选结合的方法体外培养扩增hMSCs,并进行流式细胞仪分析鉴定其免疫学表型,以未加一抗只加二抗的hMSCs作为平行对照组。选用生长良好、纯度达到95%的P5代hMSCs,用不同诱导浓度的5-氮杂胞苷(5-Azacytidine)1、5、10和20μmol/L进行诱导,对诱导后的细胞进行心肌特异性标志TroponinⅠ及Desmin的免疫组化鉴定。结果:体外分离纯化培养扩增出hMSCs,其CD44阳性率平均为93.26%±2.48%,与平行对照组(3.42%±1.09%)相比有明显差异(P<0.01)。经5和10μmol/L5-Aza诱导分化的hMSCs表达心肌特异性标记TroponinⅠ、Desmin;10μmol/L5-Aza诱导分化的hMSCs阳性率明显高于5μmol/L组;在20μmol/L组中,诱导后超过50%的细胞脱落死亡。结论:hMSCs可体外分离培养扩增,并具有向心肌细胞分化的潜能,5-Aza最佳诱导浓度为10μmol/L。     

Perfusion conditioning of hydroxyapatite-chitosan-gelatin scaffolds for bone tissue regeneration from human mesenchymal stem cells

Tissue-engineered bone grafts require an osteogenic cell source and a scaffold capable of supporting tissue regeneration. Hydroxyapatite (H), chitosan (C), and gelatin (G), when combined, produce a biomimetic scaffold with a chemical similarity to the main structural components of natural bone tissue. In this study a phase-separation technique was used to produce a porous 3D HCG scaffold, containing a network of cross-linked chitosan and gelatin fibrils coated in hydroxyapatite, with pore size readily controlled by freezing temperature. The HCG scaffolds were then seeded with human mesenchymal stem cells (hMSCs), using a depth filtration system after preconditioning with serum-containing medium for 7 days under either static or perfusion conditions. The effects of static and perfusion media preconditioning on protein adsorption, surface morphology, hMSC attachment, proliferation and osteogenic differentiation were examined. Perfusion preconditioning, as opposed to static preconditioning, enhances adsorption of ECM proteins, which in turn promotes hMSC proliferation and osteogenic differentiation. The results demonstrate the importance of convective flow in modulating the 3D HCG microenvironment and highlight its profound influence on 3D construct development.     

Human bone morphogenetic protein-2 gene transfer induces human mesenchymal stem cell proliferation and differentiation in vitro

To identify eukaryotie expression veetor of human bone morphogenetie protein 2 peDNA3/BMP2, verify its expression in transfected hulnan mesenchynlal stem cells(hMSCs) and the effect on hMSCs differentiation. Methods: The BMP2 gene was cloned into a eukaryotic expression veetor pcDNA3. Transfeeted the reeombinant into hMSCs by liposome, Lmmunnohistochemistry and it situ hybridization methods were used to identify the expression of BMP2 mRNA and protein; ALP and Von Kossa stains were performed to identify the BMP2 gene differentiated effect on the hMSCs. Resuits: The pcDNA3/BMP2 fragments were as large as theory. BMP2 mRNA and protein were espressed and synthesized both in 48 h and 4 weeks after transfeetion, the ALP and Ca deposit eshibitiio, which marked the osteogenie lineage of hMSCs, were enhanced and Sped. Conclusion: Transfeetion of pcDNA3/BMP2 is able to provide transient and persistent expressionin hMSCs, and promote the MSCs differentiation to osleogenic lineage.     

Biological characterization of long-term cultured human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) have generated a great deal of interest in clinical applications. The reason is that they may have the plasticity needed to differentiate into multiple lineages and the ability to expand ex vivo. For the therapeutic applications of hMSCs to be of practical use, it is crucial to assess the efficacy and safety of hMSCs in long-term ex vivo expansion. In this study, we cultured hMSCs by population doubling (PD) 60, and investigated their growth, osteogenic and adipogenic differential abilities, change of surface markers, telomerase activity, telomere length, and gene expression related to tumorigenesis. An in vivo tumorigenesis assay was also carried out. In long-term expanded hMSCs, the cells became aged above PD 30 and their adipogenic and osteogenic differentiation potential decreased. Telomerase activity unchanged whereas telomere length decreased and karyotypes were not changed. Gene expressions related to tumorigenesis decreased in proportion as the PD of hMSCs increased. In vivo transplantation of long-term cultured hMSCs to nude mice did not result in tumor formation. These findings suggest that diverse tests for cellular therapy should be considered during the ex vivo culture of hMSCs, particularly when a prolonged and extended propagation period is required.     

人骨髓间充质干细胞生物学特性的实验研究

目的建立人骨髓间充质干细胞体外分离、培养体系,并将其向成骨细胞定向诱导分化。方法采用梯度离心法从人骨髓血中提取骨髓间充质干细胞(m esenchym al stem cell,MSC),经体外培养扩增,观察其生物学特性。结果在体外培养条件下,骨髓MSC具有较强的增殖能力,并能被诱导向成骨细胞分化。结论建立了骨髓MSC体外分离、培养的体系,探讨了骨髓MSC的生物学特性,为进一步研究MSC作为骨组织工程的种子细胞打下了基础。     

Cellular response to oxygen containing biomedical polymers modified by Ar and He implantation

Ion beam modification is an attractive way to adapt the response of a biopolymer surface with the view to modifying cellular processes. In this work we performed Ar and He implantations into three oxygen-containing biomedical polymers: polycaprolactone (PCL), poly(ethylene glycol) (PEG) and poly(methyl methacrylate) (PMMA). An ion energy of 25keV was selected on the basis of singularities observed in simulated implantations. The implantations were carried out with fluences of 5x10(13) cm(-2) considering also the ion current density as a source of differentiated damage. The modification of the polymer structure and composition was assayed by Fourier transform infrared spectroscopy, which confirmed the selectivity of the ion current density in producing polymer film damage. Biomedical assays denoted lack of structural stability on the PMMA surfaces. Surface analysis of proteins adsorbed from fetal bovine serum on ion-beam-modified PEG were realized by quartz-crystal microbalance with dissipation, which supported the film stabilization and anti-fouling behaviour of the films. On the other hand, protein adsorption studies on micropatterned PCL surfaces were performed by time-of-flight secondary ion mass spectroscopy and revealed a clear enhancement of protein immobilization in ion-beam-modified areas. The response of human mesenchymal stem cells to the surfaces was observed to depend on the biopolymer characteristics, showing adhesion inhibition onto He-modified PEG and specially enhanced colonization onto He-irradiated PCL.