脐血间充质干细胞诱导向神经元样细胞分化的实验研究

目的：研究脐血间充质干细胞生物学特性及向神经元样细胞分化的潜能。方法：采用密度梯度离心结合贴壁培养法自脐血中分离间充质干细胞,观察细胞生长情况,描绘生长曲线,流式细胞仪检测细胞表面标志物,分别向成骨细胞、脂肪细胞、神经元样细胞进行诱导分化,通过茜素红染色、油红O染色检测脐血间充质干细胞成骨、成脂肪细胞诱导分化能力,而以免疫组织化学检测诱导后细胞表面神经标志物的表达。结果：纯化的脐血间充质干细胞贴壁生长,呈均一梭形,生长曲线呈S型,并以P3代增殖能力最强,细胞表面不表达或弱表达CD34、CD35、CD106,高表达CD29、CD44、CD105。成骨诱导2周后,可检测到钙化基质的形成,成脂肪诱导3周后,可检测到脂滴的形成。向神经元样细胞诱导分化后,可观察到典型的神经元样形态改变,且NSE、NF、GFAP阳性表达。结论：分离纯化的脐血间充质干细胞具有较强的增殖能力与分化潜能,并在体外诱导条件下可以向神经元样细胞定向分化。     

脐血间充质干细胞诱导向神经元样细胞分化的实验研究

目的:研究脐血间充质干细胞生物学特性及向神经元样细胞分化的潜能。方法:采用密度梯度离心结合贴壁培养法自脐血中分离间充质干细胞,观察细胞生长情况,描绘生长曲线,流式细胞仪检测细胞表面标志物,分别向成骨细胞、脂肪细胞、神经元样细胞进行诱导分化,通过茜素红染色、油红O染色检测脐血间充质干细胞成骨、成脂肪细胞诱导分化能力,而以免疫组织化学检测诱导后细胞表面神经标志物的表达。结果:纯化的脐血间充质干细胞贴壁生长,呈均一梭形,生长曲线呈S型,并以P3代增殖能力最强,细胞表面不表达或弱表达CD34、CD35、CD106,高表达CD29、CD44、CD105。成骨诱导2周后,可检测到钙化基质的形成,成脂肪诱导3周后,可检测到脂滴的形成。向神经元样细胞诱导分化后,可观察到典型的神经元样形态改变,且NSE、NF、GFAP阳性表达。结论:分离纯化的脐血间充质干细胞具有较强的增殖能力与分化潜能,并在体外诱导条件下可以向神经元样细胞定向分化。     

猪脂肪基质细胞成骨与成脂分化潜能的研究

目的:探索猪脂肪基质细胞体外培养和向成骨与脂肪细胞分化的条件。方法:常规方法培养猪脂肪基质细胞,分别向成骨细胞与脂肪细胞进行诱导,应用免疫组化(碱性磷酸酶法、茜素红)及油红O染色对诱导分化的细胞进行鉴定。结果:在体外培养条件下,猪的脂肪基质细胞呈成纤维样,生长旺盛,在一定的条件下,可分别被诱导分化为成骨细胞与脂肪细胞,向成骨分化的细胞表达碱性磷酸酶,在培养皿中可形成钙化斑。而在向脂肪细胞诱导分化过程中,细胞中可见有小脂滴生成,用油红O染色呈橘红色。结论:脂肪基质细胞是一种混合细胞,除了能向脂肪细胞分化外,在一定的诱导条件下,也能向成骨细胞分化。     

降钙素相关肽诱导SD大鼠骨髓间充质干细胞成骨分化的机制

目的:研究外源性降钙素基因相关肽(calcitonin gene-relate peptide,CGRP)对SD大鼠骨髓来源间充质干细胞(BMSCs)增殖和成骨分化功能的影响。方法:采用贴壁法分离骨髓间充质干细胞,扩增传代至第三代,根据分组,培养体系中添加含不同浓度(10-11～10-6mol/L)CGRP的条件培养液,WST-1法检测细胞增殖能力;碱性磷酸酶染色及钙结节染色法观察CGRP诱导BMSCs向成骨细胞分化、矿化的效果。采用RT-PCR方法检测碱性磷酸酶(ALP)、I型胶原(COLL-I)、BMP-2、RunX2、骨粘连蛋白(Osteonectin,ON)等成骨相关细胞因子mRNA的表达。结果:增殖率测定CGRP组各浓度均较对照组增加,且呈剂量依赖关系,CGRP浓度大于1×10-10mol/L时差异有显著性(P<0.05);碱磷酶染色与钙结节染色结果显示,CGRP组均有阳性显色,对照组无显色或显色不明显。CGRP组的细胞因子表达较对照组显著升高(P<0.05)。结论:适当浓度的CGRP能够直接促进体外培养的BMSCs增殖,并可短期内诱导其在向成骨细胞分化。CGRP可能在骨修复及骨重建中发挥重要的作用...     

体外定向诱导大鼠骨髓基质干细胞向成骨细胞分化的实验研究

目的研究大鼠骨髓基质干细胞的生长特点和诱导条件下的成骨能力。方法通过密度梯度离心和贴壁培养法分离成年大鼠骨髓基质干细胞,应用含地塞米松、p甘油磷酸纳和维生素c的诱导分化培养液定向诱导传代细胞向成骨细胞分化并检测碱性磷酸酶活性和细胞矿化作用。结果原代培养基质干细胞首先形成细胞集落,14d时集落间接近融合;传代细胞体积变大,约5～7d传代一次。诱导条件下,细胞碱性磷酸酶活性明显增高,并出现了矿化结节。结论骨髓基质干细胞易于分离培养及体外扩增,成骨能力肯定,可作为骨组织工程的种子细胞。     

AGEs和TNF-α对人牙周膜干细胞骨向分化能力的协同抑制作用

本实验旨在研究糖基化终末产物(AGE-BSA)和TNF-α对人牙周膜干细胞增殖及骨向分化能力的影响。本实验通过体外组织块酶消化法和有限稀释法克隆化培养牙周膜干细胞,使用流式细胞仪检测细胞表型分子stro-1、CD146、CD44、CD90的表达而对其进行干细胞鉴定后,取第3代人牙周膜干细胞在100μg/mL AGE-BSA及10 ng/mL TNF-α刺激下进行增殖能力检测;同时矿化诱导,设A组(AGE-BSA刺激组),T组(TNF-α刺激组),AT组(AGE-BSA/TNF-α共同刺激组),不含AGE-BSA/TNF-α的常规矿化诱导组作为对照;于诱导的21d茜素红染色观察钙结节形成情况,诱导7 d,碱性磷酸酶染色观察ALP活性、实时定量聚合酶链反应(real time PCR)和Western blotting检测成骨相关基因及蛋白表达情况。流式细胞仪显示细胞阳性表达STRO-1、CD146、CD44、CD90;成骨诱导21 d后茜素红染色和定量分析显示,AT组骨结节形成量最低,A组及T组相对于对照组骨结节形成量存在下降;差异均有统计学意义(p0.05)。成骨诱导7 d后ALP染色,ALP活性变化趋势与茜素红定量分析相同。成骨诱导7 d后RT-PCR检测成骨相关基因BSP、OCN、ALP mRNA表达,AT组表达水平最低,A组及T组有下降趋势,差异均有统计学意义(p0.05)。Western blotting检测显示,各组总蛋白BSP蛋白表达趋势与RT-PCR趋势相同。AGEs与TNF-α均具有对HPDLSC的骨向分化能力的抑制作用,两者共同刺激对HPDLSC骨向分化能力存在协同抑制作用。     

去卵巢骨质疏松山羊骨髓基质细胞成骨分化能力的研究

目的：研究在构建的去卵巢骨质疏松山羊动物模型中,骨髓基质细胞（MSCs）的生物学特性以及其成骨能力。方法：建立去卵巢骨质疏松山羊动物模型,使用全骨髓法获取去卵巢骨质疏松山羊（实验组）和正常山羊（对照组）MSCs,流式细胞仪检测实验组和对照组细胞周期及增殖指数（PI）;地塞米松诱导21d时油红O染色,观察成脂分化比例;成骨诱导液诱导14d,碱性磷酸酶（ALP）染色、检测ALP表达量。结果：对照组PI高于实验组;地塞米松诱导后实验组脂肪细胞比例明显高于对照组;成骨诱导第7d,对照组ALP的表达量明显高于实验组。结论：去卵巢骨质疏松山羊的MSCs增殖和成骨分化能力都降低,可能与骨质疏松症的发病机理有关。     

洛伐他汀促进成骨细胞增殖、BMP-2表达和矿化的实验研究

目的研究洛伐他汀对体外培养大鼠颅骨成骨细胞生物学功能的影响,探讨其促进骨形成的作用机制.方法洛伐他汀作用于体外培养大鼠颅骨成骨细胞,化学染色观察对成骨细胞矿化结节形成的影响;用免疫细胞化学单标计数测定成骨细胞增殖率及染色吸光度测定BMP-2的表达的变化;BMP-2和BrdU免疫双标染色吸光度测定新生成骨细胞BMP-2的表达情况.结果实验组成骨细胞矿化结节的数量和面积、细胞增殖率及BMP-2的表达明显高于空白对照组(P<0.05);实验组新生成骨细胞BMP-2的表达显著高于对照组(P<0.01).结论洛伐他汀可促进成骨细胞的增殖、分化、BMP-2的表达和矿化结节的形成,从而发挥促进骨形成的作用.     

小鼠前成骨细胞MC3T3-E1在自组装多肽水凝胶支架中的成骨分化

目的研究MC3T3-E1细胞在自组装多肽水凝胶支架上的生长和成骨分化.方法在多肽水凝胶支架RADA16上接种MC3T3-E1细胞,荧光染色观察细胞形态和存活情况;组织化学染色检测MC3T3-E1细胞碱性磷酸酶活性以及细胞外钙质沉积;RT-PCR分析成骨特异性基因的表达.结果 MC3T3-E1细胞在水凝胶支架RADA16上粘附铺展良好,呈纺锤样形态.诱导培养后支架上的细胞有较高水平的碱性磷酸酶表达和矿化基质沉积.此外,骨分化特异性基因骨桥蛋白和骨涎蛋白也有表达,且表达量随培养时间的延长而增多.结论 在自组装水凝胶内MC3T3-E1细胞可向成骨方向分化,并能在凝胶内产生矿化的细胞外基质.     

比较两种不同来源间充质干细胞的生物学特性及多向分化潜能

该文旨在比较人脂肪间充质干细胞(hADSCs)和脐带间充质干细胞(hUMSCs)的生物学特性,并鉴定其多向分化潜能。体外扩增培养hADSCs和hUMSCs,绘制细胞生长曲线并计算群体倍增时间,通过细胞集落实验比较两种细胞的增殖能力,流式细胞仪和RT-PCR方法分别检测细胞表面抗原和多能性相关基因的表达,采用成脂、成骨诱导分化试剂盒比较两种细胞的分化潜能。hADSCs和hUMSCs表达CD34、CD44、CD45、CD105的比例分别为2.7% vs 6.2%、92.3% vs 93.4%、1.3% vs 3.1%、99.4% vs 98.0%,均表达Oct4和Nanog基因;生长曲线均呈"S"型,两种细胞的群体倍增时间差异不显著(P0.05);随着代数的增加,两种细胞的增殖能力均变弱,但P7的hADSCs的增殖能力要显著优于hUMSCs(P0.05);经油红O、茜素红染色及RT-PCR和细胞免疫荧光方法检测特异基因的表达,表明两种细胞均具备成脂、成骨分化的能力,hADSCs的成脂能力优于hUMSCs,但两种间充质干细胞的成骨分化能力没有显著性差异。hADSCs和hUMSCs具有相似的生物学特性,但hADSCs可能具备更强的增殖能力和成脂分化潜能。     

Ectopic study of calcium phosphate cement seeded with pBMP-2 modified canine bMSCs mediated by a non-viral PEI derivative

We have evaluated the ectopic new bone formation effects of CPC (calcium phosphate cement) seeded with pBMP‐2 (plasmids containing bone morphogenetic protein‐2 gene) transfected canine bMSCs (bone marrow stromal cells) mediated by a non‐viral PEI (polyethylenimine) derivative (GenEscort? II) in nude mice. Canine bMSCs were transfected with pBMP‐2 or pEGFP (plasmids containing enhanced green fluorescent protein gene) mediated by GenEscort? II in vitro, and the osteoblastic differentiation was explored by ALP (alkaline phosphatase) staining, ARS (alizarin red S) staining and RT—qPCR (real‐time quantitative PCR) analysis. Ectopic bone formation effects of CPC/pBMP‐2 transfected bMSCs were evaluated and compared with CPC/pEGFP transfected bMSCs or CPC/untransfected bMSCs through histological, histomorphological and immunohistochemical analysis 8 and 12 weeks post‐operation in nude mice. Transfection efficiency was up ～35% as demonstrated by EGFP (enhanced green fluorescent protein) expression. ALP and ARS staining were stronger with pBMP‐2 gene transfection, and mRNA expression of BMP‐2 (bone morphogenetic protein‐2), Col 1 (collagen 1) and OCN (osteocalcin) in pBMP‐2 group was significantly up‐regulated at 6 and 9 days. Significantly higher NBV (new bone volume) was achieved in pBMP‐2 group than in the control groups at 8 and 12 weeks (P<0.05). In addition, immunohistochemical analysis indicated higher OCN expression in pBMP‐2 group (P<0.01). We conclude that CPC seeded with pBMP‐2 transfected bMSCs mediated by GenEscort? II could enhance ectopic new bone formation in nude mice, suggesting that GenEscort? II mediated pBMP‐2 gene transfer is an effective non‐viral method and CPC is a suitable scaffold for gene enhanced bone tissue engineering.     

骨髓间充质干细胞通过JAK／STAT3信号通路抑制树突状细胞成熟

骨髓间充质干细胞（bone marrow mesenchymal stem cells,bMSCs）具有自我更新、支持造血、多向分化和低免疫原性等特点,在调控树突状细胞（dendritic cells,DCs）成熟的过程中发挥重要作用。为了探讨bMSCs调控DCs成熟的机制,本研究通过分离培养正常捐献者bMSCs,并分离获取外周静脉血单个核细胞,诱导未成熟的树突状细胞（immature dendritic cells,imDCs）和成熟的树突状细胞（mature dendritic cells,mDCs）生成。根据Genebank中人STAT3全长基因序列,设计针对STAT3的siRNA。根据培养条件不同设计实验分组：正常bMSCs与imDCs共培养（阴性对照组）,转染siRNA的bMSCs与imDCs共培养（siRNA组）、加入JAK/STAT通路抑制剂AG490的bMSCs与imDCs共培养（AG490组）、加入TNF-α诱导的mDCs（阳性对照组）共4组,共培养72 h,流式细胞术分析DCs表型变化,ELISA检测培养液上清中IL-12水平变化。结果显示,阴性对照组不表达CD40、CD80、CD83、CD86和HLA DR标志树突细胞成熟的分子,而表达CD11b,其表型与imDCs一致;而siRNA组和AG490组的DCs表达CD40、CD80、CD83、CD86和HLA-DR等标志分子,而不表达CD11b,其表型与TNF-α诱导成熟的mDCs表型一致;siRNA组、AG490组和阳性对照组的IL-12水平较阴性对照组的IL-12水平显著升高（P＜0.05）,但siRNA组、AG490组和阳性对照组之间无明显差异（P＞0.05）。以上结果表明,通过siRNA和抑制剂AG490阻断bMSCs中JAK/STAT3通路促进了imDCs的成熟,提示bMSCs通过JAK/STAT3通路参与调控imDCs成熟。     

Bone regeneration by BMP-2 enhanced adipose stem cells loading on alginate gel

Adipose stem cells (ASCs) have the potential to differentiate into a variety of cell lineages both in vitro and in vivo. In this study, ASCs were harvested from normal Sprague–Dawley (SD) rats and transfected by BMP-2 gene before they were loaded on alginate. The ability of bone regeneration was determined in rat critical-size cranial defects. An 8-mm diameter defect was created in the calvarias of 36 rats; these rats were divided into three groups. In experimental group, the defects were filled with alginate gel combined with BMP-2 transfected ASCs; in negative control group, the defects were filled with alginate gel mixed with normal ASCs; in blank controls, the defects were filled with cell-free alginate gel. Four rats of each group were killed and the cranial defect sites were observed at 4, 8 and 16 weeks after surgery. There was complete repair of cranial defects in experimental group using the alginate gel loading BMP-2 transfected ASC, but only partial repair in negative controls and in the blank control. The engineering approach combining BMP-2 enhanced ASCs with alginate gel can therefore stimulate bone regeneration and repair for the large size bone defects.     

Osteogenic Differentiation of Human Mesenchymal Stem Cells in Mineralized Alginate Matrices

Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering.     

Uniparental parthenogenetic embryonic stem cell derivatives adaptable for bone and cartilage regeneration

Cells with the desired phenotype and number are critical for regenerative medicine and tissue engineering. Uniparental parthenogenetic embryonic stem cells (pESCs) share fundamental properties with embryonic stem cells. This study aims to determine the viability of pESC-based tissue engineering for bone and cartilage reconstruction. The mouse pESCs were cultured in suspension to form embryoid bodies. An adherent cultivation approach was employed to obtain parthenogenetic embryonic mesenchymal stem cells (pMSCs) from the embryoid bodies. Then, the pMSCs were cultured in conditional media to differentiate into osteogenic and chondrogenic lineages. The pESC-derived osteoblasts and chondroblasts were seeded into coral and sodium alginate scaffolds, respectively. The cell-seeded scaffolds were implanted into dorsal subcutaneous pockets of nude mice to evaluate ectopic reconstruction of bone and cartilage. We demonstrated that pESCs display the capacity to differentiate into all three germ layers. The generated pMSCs were able to differentiate into osteogenic and chondrogenic lineages, which survived well after seeding into coral and alginate acid scaffolds. Six weeks after cell-scaffold implantation, gross inspection and histological examination revealed that ectopic bone and cartilage tissues had successfully regenerated in the specimen. According to the findings of this study, pESC derivatives have a high potential for bone and cartilage regeneration.     

P物质在BMSCs来源的成骨细胞与内皮细胞体外联合培养中的作用

目的:观察P物质(substance P,SP)在BMSCs来源的成骨细胞与内皮细胞体外联合培养中的作用,研究P物质作用于种子细胞的最适浓度指导组织工程骨修复骨缺损。方法:采用新生新西兰大白兔胎兔(雌雄不限)密度梯度离心法分离骨髓间充质干细胞行体外培养和连续传代,获得较纯的BMSCs。取生长状态良好的第3代BMSCs行成骨诱导培养及成血管内皮细胞诱导培养并鉴定。将诱导7 d的两种细胞按2:1比例混合培养,待细胞传至2代加入不同浓度的SP作为实验组,以正常未加SP的细胞培养基为对照组。培养后1、3、5、7 d采用CCK-8法测定细胞增殖并绘制生长曲线,观察细胞生长数量,测定碱性磷酸酶活性及观察细胞周期分布。结果:浓度范围从1×10-12-1×10-6mol/L的SP对联合共培养的成骨细胞增殖和活性都有促进作用,在浓度为1×10-8mol/L对联合共培养的成骨细胞增殖和活性的作用功效最强。结论:在体外直接联合共培养的体系中,SP对新种子细胞促进效果明显,其在1×10-8mol/L对联合共培养的成骨细胞增殖和活性作用最强。     

Effects of ovariectomy and tamoxifen on rat bone tissue: histomorphometric and histopathologic study

OBJECTIVE: To investigate possible detrimental effects on bone tissue induced by ovariectomy and tamoxifen (TMX) using bone densitometry and histomorphologic analysis. STUDY DESIGN: Twenty-four rats were allocated into 4 groups: group 1, intact normal rats (n = 6); group 2, ovariectomized rats (n = 6); group 3, normal female rats that received 1 mg/kg/day TMX dissolved in dimethyl sulfoxide (DMSO) for 2 months (n = 6); group 4, normal female rats that received DMSO for the same duration and with a volume equal to that of TMX (n = 6). Results of histomorphometric analysis for trabecular thickness, number of osteoblasts and osteoclasts, trabecular number, and area and cortical thickness were compared. RESULTS: No significant effects of ovariectomy on femoral or lumbar bone mineral density (BMD) were found. In the TMX group, the value of femoral BMD increased significantly compared to control group cellular and pathologic changes. TMX caused significant decrease in osteoblasts compared to the control group. CONCLUSION: TMX has a positive effect on inorganic bone tissue, but a negative effect on number of osteoblasts and osteoclasts. Future studies investigating estrogenic and antiestrogenic effects of TMX should include cellular parameters related to proliferation using histopathologic and histomorphometric analyses.     

体外构建组织工程化软骨的初步研究

观察用藻酸钠凝胶在体外长期培养软骨细胞的情况,为求进一步用藻酸钠凝胶在体外构建组织工程化软骨提供初步研究.将传代培养的、细胞终浓度为1×107/mL的软骨细胞复合藻酸钠凝胶,注入圆柱形模具中,将模具分别浸入100、200、300 mmol/L的固化剂氯化钙溶液中,固化15 min使其成形,于体外培养2、4、6周后,行HE染色、阿尔新蓝染色,了解软骨细胞的生长情况.2、4、6周时软骨细胞与藻酸钙凝胶复合良好并能在其中保持活性及分裂能力,且在6周时出现类软骨变化.因此藻酸钠凝胶是可用于体外构建组织工程化软骨的生物材料.     

下颌骨牵张成骨中不同牵张频率对牵张区成骨细胞增殖细胞核抗原表达的影响

目的:对比研究下颌骨牵张成骨中不同牵张频率的作用下新骨组织中成骨细胞的增殖活性,从而筛选出最佳牵张频率。方法:选用16只3月龄的幼年山羊,随机分为4组,每组4只,第1组为对照组,分别对第2、3、4组动物右下颌骨行骨皮质切开术后进行牵张,第2组牵张频率为2次/天,第3组牵张频率为4次/天,第4组牵张频率为6次/天,于完成牵张后4周时分别处死动物,取牵张区新骨组织和对照组右下颌骨颏孔区骨组织行PCNA免疫组化染色并进行组间比较。结果:各牵张组牵张区新生骨组织中成骨细胞PCNA表达的阳性细胞数均显著高于对照组,6次/天牵张组和4次/天牵张组牵张区中成骨细胞PCNA表达的阳性细胞数显著高于2次/天牵张组,但6次/天牵张组和4次/天牵张组成骨细胞PCNA表达的阳性细胞数无显著性差异。结论:在下颌骨牵张成骨进程中,随着牵张频率的增加,牵张区成骨细胞的增殖能力提高,可能术后成骨效果更佳。