人端粒酶逆转录酶启动子调控的重组腺病毒的构建及其在膀胱癌细胞中的表达

目的构建人端粒酶逆转录酶（hTERT）启动子调控的表达增强型绿色荧光蛋白（EGFP）的腺病毒系统，观察其在膀胱癌细胞中的表达。方法构建带有hTERT启动子的腺病毒穿梭载体pDC315-Tp—EGFP，细胞重组技术获得腺病毒Ad-hTERT-EGFP，按感染复数（MOI）100体外转染膀胱癌细胞株253J及人胚肺成纤维细胞株MRC-5，通过倒置荧光显微镜和Rt—PCR分别检测EGFP的表达。带有小鼠巨细胞病毒（mCMV）启动子的腺病毒Ad-EGFP作为阳性对照。结果成功构建出重组腺病毒Ad-hTERT-EGFP，滴度为3．8×10^10空斑形成单位（pfu）／ml，Ad—hTERT-EG-FP感染的253J细胞中，（85．2±3．3）％发出明亮的绿色荧光；而其感染的MRC-5细胞未产生绿色荧光（P〈0．01）；对照病毒Ad-EGFP在253J和MRC-5中分别有（87．1±2．2）％及（92．5±3．1）％的细胞可见到绿色荧光。RT-PCR检测显示：253J细胞转染Ad-hTERT-EGFP、Ad-EGFP后及MRC-5细胞转染Ad-EGFP后均有EGFP基因表达；而MRC-5细胞转染Ad-hTERT-EGFP后未见EGFP基因表达。结论该腺病毒系统中hTERT启动子调控下游基因可选择性地在膀胱肿瘤细胞中表达，在正常细胞中不表达，具有明显的靶向性。     

人β干扰素基因重组腺病毒载体的构建及在骨髓间充质干细胞的表达

目的 构建人β干扰素(hIFN-β)基因重组腺病毒,观察重组腺病毒介导的hIFN-β转染大鼠骨髓间充质干细胞(MSCs)后,细胞内hIFN-β表达情况以及重组腺病毒对MSCs生长的影响.方法 利用细菌内同源重组技术快速构建Ad-hIFN-β腺病毒重组质粒,经酶切及测序鉴定正确后转染人胚肾细胞HEK293包装成为重组Ad-hIFN-β腺病毒,并进行滴度测定.转染的MSCs行逆转录-聚合酶链反应(RT-PCR)检测细胞内hIFN-β mRNA的表达;酶联免疫吸附试验(ELISA)法检测培养液上清hIFN-β的分泌情况;噻唑蓝(MTF)比色法检测细胞活力并绘制转染后MSCs生长曲线.结果 经限制性内切酶检测、基因测序及和绿色荧光观察证实成功的构建了携带hIFN-β基因的重组腺病毒,且重组腺病毒滴度高达1×109pfu/ml.Ad-hIFN-β转染MSCs后在荧光显微镜下证实有绿色荧光;RT-PCR证明转染的MSCs内有hIFN-β mRNA的表达;ELISA检测转染组1、3、5、7、10、15、20 d上清液中hIFN-β蛋白分泌量分别为192、273.436、957、605、472、279 ng/L,明显高于对照组(P<0.01);Ad-hIFN-β转染的MSCs生长曲线与正常培养MSCs差异无统计学意义(P>0.05).结论 成功构建了携带hIFN-β基因的重组腺病毒载体,重组腺病毒转染对MSCs的增殖能力无明显影响,而且Ad-hIFN-β转染大鼠MSCs能够表达并分泌hIFN-β蛋白.     

小鼠CXCR4腺病毒的构建及其转染对MSCs向受损肝脏归巢的影响

目的:观察小鼠CXCR4腺病毒(Ad-mCXCR4)转染对骨髓间充质干细胞(MSCs)受损肝脏归巢的影响。方法:分离小鼠MSCs并体外扩增、鉴定;从小鼠肝脏组织中获得CXCR4目的基因,用同源重组法构建腺病毒载体Ad-mCXCR4并鉴定;用Ad-mCXCR4转染MSCs,以转染空载体Ad-vector和未转染的MSCs为对照,然后用Western blot法检测各组细胞CXCR4蛋白的表达;小鼠注射CCl4诱导肝损伤模型后随机分为3组,分别通过尾静脉注射转染Ad-mCXCR4,Ad-vector和未转染的MSCs,48 h后用激光共聚焦观察各组MSCs归巢到受损肝组织的情况。结果:成功构建小鼠CXCR4腺病毒载体Ad-mCXCR4;MSCs转染Ad-mCXCR4后CXCR4蛋白呈高表达,而转染Ad-vector和未转染的MSCs无CXCR4蛋白表达;注射未转染MSCs组小鼠肝脏未见绿色荧光蛋白阳性细胞,注射Ad-mCXCR4-MSCs组小鼠较注射转染Ad-vector-MSCs组小鼠肝脏绿色荧光蛋白阳性细胞明显增加[(21.25±1.56)vs.(5.42±0.81)](P<0.01)。结论:基因修饰可提高MSCs的CXCR4表达,高表达CXCR4的MSCs向受损肝脏归巢增加。     

转化生长因子β3基因转染兔骨髓间充质干细胞的实验研究

目的构建转化生长因子β3（transforming growth factor β3，TGF-β3）的腺病毒载体，并通过腺病毒载体将TGF-β3基因转染骨髓间充质干细胞（marrow mesenchymal stem cells，MSCs），使其在细胞内得到表达。方法将人TGF-β3质粒定向克隆进入穿梭质粒pAdTrack—CMV中，与pAdEasy-1共同转入细菌并重组，获得TGF-β3重组腺病毒质粒，用脂质体法导入包装细胞HEK293中，48～96h后荧光显微镜下观察绿色荧光蛋白的表达。取1月龄新西兰大白兔5只，取其胫骨骨髓。采用密度梯度离心法分离纯化MSCs，并进行传代。取传至第3代细胞采用TGF-β3腺病毒载体转染，10h后荧光显微镜观察绿色荧光表达，转染TGF-β3重组腺病毒4d后的MSCs用免疫细胞化学方法观察TGF-β3在细胞内的表达。结果pAdEasy—TGF-β3转染HEK293细胞48～96h后，荧光显微镜可见明显的绿色荧光表达。兔骨髓分离培养10d后，培养MSCs融合达70％～80％、贴壁紧密，细胞形态均一，似成纤维细胞；14d完成原代细胞培养。TGF-β3重组腺病毒转染MSCs17h后，荧光显微镜下出现少量绿色荧光，48～72h荧光加强，荧光与MSCs轮廓一致。免疫细胞化学观察，转染TGF-β3重组腺病毒MSCs胞浆内有棕黄色阳性颗粒表达。结论TGF-β3基因重组腺病毒载体的成功构建并在MSCs内的表达，为创伤愈合的基因治疗提供了研究基础。     

siRNA c-Met腺病毒转染对人外泌汗腺上皮细胞增殖的影响

目的：研究siRNA c-Met腺病毒转染对培养的人外泌汗腺上皮细胞（human eccrine sweat gland epithelial cells,hESGc）增殖的影响。方法：按我科已经建立的方法培养和鉴定hESGc,取第1代细胞备用。构建表达红色荧光蛋白的siRNA c-Met腺病毒,荧光显微镜观察和Westernlot检测证实病毒的有效性。MTT法检测siRNA c-Met腺病毒对hESGc增殖的影响。结果：荧光显微镜下可见转染了siRNA c-Met腺病毒的hESGc有红色荧光表达,转染后48h,收集细胞进行westernblot检测,结果发现,siRNA c-Met腺病毒转染能抑制hESGc细胞中c-Met蛋白的表达,抑制率达70%以上,MTT法检测发现转染siRNA c-Met腺病毒能抑制hESGc增殖,抑制率分别为16.8%（2天）和34.5%（4天）。结论：siRNA c-Met腺病毒转染能抑制hESGc的增殖。     

PTEN编码蛋白对TGF-β1刺激大鼠肾成纤维细胞增殖和ColⅣ与FN分泌的抑制作用

目的：观察张力蛋白同源物基因（PTEN）编码蛋白对转化生长因子-β1（TGF-β1）刺激所致大鼠肾成纤维细胞增殖和Ⅳ型胶原（ColⅣ）、纤连蛋白（FN）分泌的影响。方法：用重组PTEN腺病毒转染体外培养大鼠肾成纤维细胞,倒置荧光显微镜检测绿色荧光蛋白表达,RT-PCR检测PTEN mRNA表达。转染36h后TGF-β1体外刺激,TGF-β1刺激24h后MTT法检测细胞增殖活力,免疫细胞化学法检测PCNA表达,ELISA法检测细胞上清中ColⅣ、FN水平。结果：PTEN腺病毒转染36h后可见明显绿色荧光蛋白表达,PTEN mRNA表达明显增多（P〈0.01）。PTEN腺病毒转染后给予TGF-β1刺激组较单纯TGF-β1刺激组平均光密度值（OD）显著降低（P〈0.01）,PCNA表达显著减少（P〈0.01）,且ColⅣ、FN的分泌水平明显下降（P〈0.05）。结论：PTEN基因编码蛋白能抑制TGF-β1刺激所致大鼠肾成纤维细胞增殖、PCNA表达及ColⅣ、FN分泌,可能具有抑制残肾纤维化、延缓残肾毁损速度的作用。     

RNA干扰抑制yrdC蛋白表达对人胃癌细胞株BGC-823体外增殖能力的影响

目的:构建针对人yrdC基因siRNA的重组腺病毒Ad-shyrdC并观察其转染人胃癌细胞株BGC-823后对细胞体外增殖能力的影响。方法:筛选高效抑制yrdC蛋白表达的RNAi位点,并构建表达siRNA的重组腺病毒,转染人胃癌细胞株BGC-823后以Western印迹法鉴定细胞yrdC蛋白表达的变化;同时通过MTT法、流式细胞术分别测定BGC-823细胞增殖活性和增殖指数的变化。结果:成功构建了抑制人yrdC基因siRNA的重组腺病毒Ad-shyrdC;转染BGC-823细胞后可明显抑制yrdC蛋白表达,并使所测定的细胞MTT值和细胞增殖指数提示BGC-823细胞增殖活性下降(P<0.05)。结论:腺病毒介导的RNAi能有效地抑制BGC-823细胞中yrdC蛋白表达,并降低其增殖活性。     

BMP-12重组腺病毒载体转染外周血MSCs向肌腱/韧带细胞分化研究

目的探讨携带BMP-12基因的腺病毒载体转染诱导外周血MSCs向肌腱/韧带细胞分化的效果。方法取3~4月龄新西兰兔外周血,体外分离培养外周血MSCs至第3代。采用Ad Easy腺病毒载体系统制备BMP-12重组腺病毒载体。将BMP-12重组腺病毒体体外转染第3代外周血MSCs,转染后24 h通过流式细胞术(flow cytometry,FCM)检测转染效率,倒置相差显微镜观察细胞形态变化,转染后8、24 h在荧光显微镜下观察绿色荧光蛋白(green fluorescent protein,GFP)表达;转染后0、7、14 d,采用免疫组织化学染色观察I型胶原表达情况;实时定量PCR检测肌腱/韧带特异基因Tenomodulin、Tenascin-C和Decorin m RNA表达水平,并设未转染细胞作为对照组。结果转染后24 h,倒置相差显微镜观察示细胞生长增殖缓慢,细胞形态清晰;FCM检测示,转染组转染效率为99.57%,未转染组为2.46%;转染后8 h,荧光显微镜下即可见GFP表达,随培养时间延长GFP表达逐渐增多,24 h时几乎所有细胞均可见GFP表达。免疫组织化学染色示,随转染时间延长,Ι型胶原表达逐渐增强;转染组转染后14 d,肌腱/韧带特异基因Tenomodulin、Tenascin-C和Decorin m RNA表达水平分别为0.061±0.013、0.029±0.008、0.679±0.067,均显著高于未转染组的0.004±0.002、0.003±0.001、0.142±0.024,差异有统计学意义(t=—7.700,P=0.031;t=—5.741,P=0.020;t=—12.998,P=0.000)。结论 BMP-12重组腺病毒载体可明显促进外周血MSCs向肌腱/韧带成纤维细胞表型分化,并促进肌腱/韧带特异基因表达和细胞外基质产生,为外周血MSCs用于肌腱/韧带再生提供了依据。     

重组腺病毒介导的β-神经生长因子基因转染大鼠内皮祖细胞的实验研究

[目的]探究携带β-神经生长因子(β-NGF)基因的重组腺病毒转染大鼠骨髓源内皮祖细胞(EPCs)的最佳感染复数(MOI),并从基因转录和蛋白合成两个水平上观察转染后EPCs对β-NGF基因的表达,探讨其对脊髓损伤后神经元细胞微环境的影响。[方法]密度梯度离心法分离、全骨髓贴壁法培养大鼠骨髓源EPCs,免疫荧光法检测EPCs特异性表面分子CD34、CD133和VEGFR-2的表达。用不同MOI值的携带β-NGF基因和绿色荧光蛋白基因(GFP)的重组腺病毒转染EPCs,确定最佳的MOI值。用携带β-NGF基因的重组腺病毒转染的细胞为β-NGF基因组,用空载的重组腺病毒转染的细胞为空载组,未转染的细胞为空白组。RT-PCR法、Western blot法和ELISA法检测β-NGF的表达。[结果]成功分离、培养出大鼠骨髓源EPCs,特异性表面分子CD34、CD133和VEGFR-2经鉴定呈阳性表达;携带β-NGF基因的重组腺病毒转染EPCs最佳的MOI为70;转染成功的细胞β-NGF基因在m RNA和蛋白两个不同的水平上表达都升高,并持续向细胞外分泌。[结论]携带β-NGF基因的重组腺病毒可成功转染EPCs,成功转染β-NGF基因的细胞能持续向细胞外分泌有活性的β-NGF蛋白。     

人骨形态发生蛋白-2基因转染兔骨髓基质干细胞及其表达

目的探讨含有人骨形态发生蛋白-2(hBMP-2)cDNA的真核表达载体在兔骨髓基质干细胞(MSCs)中的转录及表达情况,为进一步进行多基因转染MSCs复合纳米仿生骨治疗骨缺损实验提供材料。方法用电穿孔方法将真核表达载体pIRES2-EGFP-hBMP2转染至兔MSCs中,荧光显微镜及流式细胞学检查观察转染效果、检测转染效率,定量RT-PCR方法观察hBMP-2cDNA在兔MSCs中的转录情况,免疫组织化学及westernblot方法检测hBMP-2蛋白表达情况,ALP活性定量测定检测hBMP-2蛋白功能。结果电穿孔方法将重组质粒转染至兔MSCs中,荧光显微镜下观察到绿色荧光蛋白表达,流式细胞仪检测转染效率为(42.7±2.1)%,转染24h后定量RT-PCR方法检测到hBMP-2cDNA在兔MSCs中的转录片断,免疫组织化学观察到hBMP-2蛋白呈强阳性表达,westernblot方法可见18KDhBMP-2蛋白条带,转染组细胞ALP活性明显提高(P>0.05)。结论pIRES2-EGFP-hBMP2通过电穿孔方法导入兔MSCs,并在其中有效表达,发挥生物学作用。     

Systemic infusion of FLK1(+) mesenchymal stem cells ameliorate carbon tetrachloride-induced liver fibrosis in mice

BACKGROUND: Fibrosis is the common end stage of most liver diseases, for which, unfortunately, there is no effective treatment available currently. It has been shown that mesenchymal stem cells (MSCs) from bone marrow (BM) could engraft in the lung after bleomycin exposure and ameliorate its fibrotic effects. This study was designed to evaluate the effect of Flk1 MSCs from murine BM (termed here Flk1 mMSCs) on fibrosis formation induced by carbon tetrachloride (CCl4). METHODS: A CCl(4)-induced hepatic fibrosis model was used. Flk1 mMSCs were systemically infused immediately or 1 week after mice were challenged with CCl(4). Control mice received only saline infusion. Fibrosis index and donor-cell engraftment were assessed 2 or 5 weeks after CCl(4) challenge. RESULTS: We found that Flk1 mMSCs transplantation immediately, but not 1 week after exposure to CCl(4), significantly reduced CCl(4)-induced liver damage and collagen deposition. In addition, levels of hepatic hydroxyproline and serum fibrosis markers in mice receiving immediate Flk1 mMSCs transplantation after CCl(4) challenge were significantly lower compared with those of control mice. More importantly, histologic examination suggested that hepatic damage recovery was much better in these immediately Flk1 mMSCs-treated mice. Immunofluorescence, polymerase chain reaction, and fluorescence in situ hybridization analysis revealed that donor cells engrafted into host liver, had epithelium-like morphology, and expressed albumin, although at low frequency. CONCLUSION: These results suggest that Flk1 mMSCs might initiate endogenous hepatic tissue regeneration, engraft into host liver in response to CCl(4) injury, and ameliorate its fibrogenic effects.     

红细胞生成素对模拟急性肾损伤微环境下培养骨髓间充质干细胞增殖的影响及机制探讨

目的 观察经红细胞生成素（EPO）干预后,体外模拟急性肾损伤（AKI）微环境下培养骨髓间充质干细胞（MSC）的分裂增殖情况,并探讨产生这种变化的可能机制。 方法 抽取C57BL/6小鼠的骨髓,经Percoll密度梯度离心联合贴壁培养法分离纯化出小鼠MSC（mMSC）,以流式细胞仪鉴定。夹闭雄性C57BL/6小鼠双侧肾蒂30 min再开放30 min的方法制作AKI鼠模型,即刻取双侧肾脏皮质制作缺血再灌注（IR）肾脏匀浆上清。取扩增第3代的mMSC分组培养：A组：含10%胎牛血清的低糖DMEM培养基;B组：含10%胎牛血清的低糖DMEM培养基＋IR肾脏匀浆上清,体外模拟AKI微环境干预mMSC;C组：含10%胎牛血清的低糖DMEM培养基＋IR肾脏匀浆上清+不同浓度EPO（1、5、10、50 U/ml）。培养1、3、5、7 d。CCK-8法检测各组培养mMSC的增殖,TUNEL法检测mMSC凋亡,Western印迹法检测mMSC表面EPO受体（EPOR）及增殖凋亡相关信号通路蛋白的表达。 结果 CCK-8法检测显示,经IR肾脏匀浆上清干预后,不同时间点mMSC的增殖效应显著减弱（P ＜ 0.01）,而TUNEL检测表明其胞核染色阳性细胞的百分比显著高于A组（P ＜ 0.01）;给予EPO干预后,mMSC的增殖能力增强,胞核染色阳性细胞百分比降低,具有浓度依赖效应。Western印迹结果显示,第3代mMSC表面存在EPOR表达,培养5 d后EPOR相对表达量为0.092±0.015。EPO以剂量和时间依赖性降低AKI微环境下凋亡相关蛋白caspase-3的表达,同时上调凋亡抑制蛋白Bcl-2的表达。用10 U/ml EPO干预5 d后,相对于B组,磷酸化蛋白酪氨酸激酶2及磷酸化信号转导和转录因子的表达均显著上调（均P < 0.01）。 结论 EPO能促进体外AKI微环境干预下培养mMSC的增殖,减轻其凋亡,该效应经EPOR介导,并与增殖凋亡相关信号通路蛋白有关。     

Novel mesenchymal stem cell delivery system as targeted therapy against neuroblastoma using the TH-MYCN mouse model

PurposeMesenchymal stem cells (MSCs) are reported to migrate toward damaged tissues or tumors. We previously reported the in vivo short-term (1 day) tumor-homing effect of xenogeneic human MSCs (hMSCs) using the TH-MYCN mouse neuroblastoma model (MYCN-TgM). In this study, we analyzed the long-term tumor-homing effect of allogeneic mouse MSCs (mMSCs) and explored the antitumor effect and drug delivery function of mMSCs.MethodsmMSCs were administered intraperitoneally (i.p.) to MYCN-TgM and traced by an in vivo imaging system (IVIS). We administered green fluorescent protein (GFP)-transduced mMSCs into MYCN-TgM i.p. and examined the cell survival by immunohistochemistry. We also administered interferon beta-transduced mMSCs (mMSCs-IFN-β) to MYCN-TgM i.p. and measured the concentration of IFN-β in the tumor and organs by an enzyme-linked immunosorbent assay (ELISA). The survival curves of MYCN-TgM administered every week was analyzed.ResultsThe IVIS revealed the accumulation of fluorescence was observed in the tumor both in vivo and after excision. Immunohistochemistry using anti-GFP antibody revealed that the mMSCs existed within the tumor until 14 days but not in the organs. The ELISA showed increased concentrations of IFN-β only in the tumors, with the values gradually diminishing over 14 days. The mMSCs-IFN-β group survived significantly longer than the control group (p < 0.03), while the mMSCs-alone group did not show a survival advantage.ConclusionsAllogeneic mMSCs showed a homing ability for mouse neuroblastoma and existed within the tumor for as long as two weeks. This may be a candidate drug delivery vehicle for antitumor agents against neuroblastoma.Level of evidence     

多药耐药基因转染骨髓造血细胞移植小鼠的安全性研究

目的 探讨多药耐药基因(mdrl)转染骨髓造血细胞移植后,其在体内分布和安全性.方法 骨髓造血细胞转染mdrl基因后移植入BALB/C鼠,免疫组织化学和RT.PCR观察mdrl基因在骨髓、外周血及重要脏器的表达;监测外周血白细胞变化及重要脏器病检分析其安全性.结果 P-糖蛋白(P-gP)在骨髓表达率随时间降低,各时间组差异无统计学意义(x2=3.74,P＞0.05),在外周血表达第2月最高,为(9.95±1.84)%,各时间组差异无统计学意义(x2=2.31,P＞0.05),在重要脏器无表达;移植未转染组与移植转染组外周血白细胞计数至移植60 d后,两者差异有统计学意义(t=6.173,P＜0.05),病检除肝和肾有炎性渗出和水肿病变外,其余无异常.结论 mdrl基因在骨髓和外周血有持续较高表达,在重要脏器无表达;mdrl基因转染对造血恢复及重要脏器无明显影响.     

骨髓间充质干细胞干预对急性肾损伤鼠肾脏中细胞因子的影响

目的：建立缺血再灌注（I/R）诱导的急性肾损伤小鼠模型,探讨外源性地给予骨髓间充质干细胞（MSCs）干预对模型小鼠肾损伤微环境中细胞因子水平的影响,并探讨其在肾损害修复中的作用。方法：采用Percoll密度梯度离心法分离出C57BL/6小鼠的骨髓间充质干细胞（mMSCs）。雄性C57BL/6小鼠45只,分为正常对照组（15只）、I/R组（15只、夹闭双侧肾蒂30min开放）、I/R＋mMSCs组（15只、夹闭双侧肾蒂30min开放的同时尾静脉注射mMSCs）。于建模后1d、2d、3d、7d、14d分别处死部分小鼠（每次每组均处死3只）,留取动脉血及肾组织,检测血尿素氮（BUN）及肌酐（Scr）水平,制作肾组织切片行HE染色,观察肾组织病理变化,行肾小管坏死程度评分（ATN评分）。ELISA法检测肾组织匀浆肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、单核细胞趋化蛋白-1（MCP-1）、白细胞介素-10（IL-10）、肝细胞生长因子（HGF）、骨形态发生蛋白-7（BMP-7）的水平。结果：I/R组小鼠的BUN及Scr均显著高于正常对照组,肾小管损伤严重;而I/R＋mMSCs组小鼠的BUN及Scr水平较I/R组为低,以术后第7天差异最为显著（P〈0.01）,肾小管损伤病理明显减轻,ATN评分也有着显著降低。ELISA结果显示单纯I/R组各时间点肾组织匀浆中TNF-α、IL-1β、MCP-1的水平显著升高（P〈0.01或P〈0.05）,而IL-10、HGF、BMP-7的水平却有着显著降低（P〈0.01或P〈0.05）。但同时给予MSCs干预的I/R小鼠肾组织匀浆中前述细胞因子的水平却向着相反方向改变。结论：MSCs对I/R肾组织中细胞因子的分泌具有调控作用,而这些调控了的细胞因子进而可通过旁分泌作用发挥促进肾损害的修复作用。     

pcDNA_(3.1)-OGP基因转染兔骨髓基质干细胞的表达及生物学效应的观察

[目的]观察成骨生长肽(osteogenic growth peptid,OGP)基因转染兔骨髓基质干细胞后的表达及表达产物对骨髓基质干细胞向成骨细胞分化的影响.[方法]构建重组真核表达载体pcDNA_(3.1)-OGP,并在脂质体介导下,将其导入兔骨髓基质干细胞.通过G418筛选获得阳性克隆.用RT-PCR方法榆测OGP基因在骨髓基质干细胞内的表达.Ⅰ型胶原和碱性磷酸酶的检测观察转染pcDNA_(3.1)-OGP后骨髓基质干细胞向成骨细胞分化情况.[结果]成功构建真核表达载体pcDNA_(3.1)-OGP,用RT-PCR方法及碱性磷酸酶和Ⅰ型胶原检测证实OGP基因能在骨髓基质干细胞中表达并促进其向成骨细胞分化.[结论]经pcDNA_(3.1)-OGP转染的兔骨髓基质干细胞不仅可以表达OGP,而且具有向成骨细胞系分化的特性.     

Vascularized bone marrow transplantation: A new surgical approach using isolated femoral bone/bone marrow

BACKGROUND: Orthotopic composite tissue (limb) transplantation in rats is a unique model for vascularized bone marrow transplantation because bone marrow cells and bone marrow stroma are transplanted by microsurgical means, thus creating immediate bone marrow space and engraftment. However, it contains a skin component and other musculoskeletal tissues that complicate issues related to tolerance induction. MATERIALS AND METHODS: To study only aspects of vascularized bone marrow transplantation, we created a new isolated vascularized bone marrow transplant model in rats. The common iliac (or femoral) artery and vein were microsurgically anastomosed to the recipient abdominal aorta and inferior vena cava in an end-to-side fashion, respectively. Syngeneic male Lewis (RT1(1), n = 20) and allogeneic male BN (RT1(n), n = 10) donors were transplanted to female Lewis recipients. To establish rejection criteria, we examined histopathology and used the polymerase chain reaction (PCR) to assess microchimerism of donor male bone marrow cells in the peripheral blood of female recipients using rat Y chromosome (sex-determining region Y)-specific primers. RESULTS: All recipients were healthy and remained stable without major complications for up to 300 days posttransplant. Morphologically, syngeneic male Lewis bone marrow showed a near-normal appearance. Allogeneic male BN bone marrow was clearly rejected. Male bone marrow cells were detected by PCR in the peripheral blood of all syngeneic recipients, but not in allogeneic blood specimens. CONCLUSIONS: A new surgical approach to bone marrow transplantation was established. This consisted of the vascularized femoral bone/bone marrow transplant. Further analyses regarding the ability of vascularized femoral bone marrow transplants to induce systemic transplantation tolerance in adult rats will provide insights into not only various issues of immunology but also the potential clinical application of vascularized bone marrow transplantation.     

Fluorescence molecular tomography enables in vivo visualization and quantification of nonunion fracture repair induced by genetically engineered mesenchymal stem cells

Fluorescence molecular tomography (FMT) is a novel tomographic near‐infrared (NIR) imaging modality that enables 3D quantitative determination of fluorochrome distribution in tissues of live small animals at any depth. This study demonstrates a noninvasive, quantitative method of monitoring engineered bone remodeling via FMT. Murine mesenchymal stem cells overexpressing the osteogenic gene BMP2 (mMSCs‐BMP2) were implanted into the thigh muscle and into a radial nonunion bone defect model in C3H/HeN mice. Real‐time imaging of bone formation was performed following systemic administration of the fluorescent bisphosphonate imaging agent OsteoSense?, an hydroxyapatite‐directed bone‐imaging probe. The mice underwent imaging on days 7, 14, and 21 postimplantation. New bone formation at the implantation sites was quantified using micro‐computed tomography (micro‐CT) imaging. A higher fluorescent signal occurred at the site of the mMSC‐BMP2 implants than that found in controls. Micro‐CT imaging revealed a mass of mature bone formed in the implantation sites on day 21, a finding also confirmed by histology. These findings highlight the effectiveness of FMT as a functional platform for molecular imaging in the field of bone regeneration and tissue engineering. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:522–530, 2008     

Xenogeneic bone marrow transplantation: I. Cloning, expression, and species specificity of porcine IL-3 and granulocyte-macrophage colony-stimulating factor

Abstract: Establishment of mixed bone marrow chimerism has been used to induce tolerance to solid organ transplants in several allograft and xenograft models. The species specificity displayed by some important hematopoietic cytokines potentially limits the efficacy of this approach in pig-to-primate models. In order to examine the role porcine-specific factors may play in the establishment of xenogeneic mixed bone marrow chimerism, we have cloned and heterologously expressed the genes encoding porcine IL-3 and granulocyte-macrophage colony-stimulating factor, two myeloid growth factors previously shown to have significant species specificity. The purified porcine factors are demonstrated here to be potent stimulators of porcine bone marrow cell proliferation, but to have little or no effect on primate cells. The species specificity of these factors is reciprocal, in that the corresponding human cytokines have little activity I on porcine bone marrow cells.