VEGF真核表达载体构建及其在骨髓间充质干细胞中的表达

目的构建血管内皮生长因子（vascu lar endothelial growth factor,VEGF）真核表达载体,并研究其在骨髓间充质干细胞（m esenchym al stem cells,MSCs）中的表达情况。方法运用DNA重组技术,构建VEGF真核表达载体pcDNA3.1（-）/hVEGF165,将载体转染大鼠MSCs,RT-PCR,ELISA及免疫细胞化学等方法检测VEGF在大鼠MSCs中的表达情况,MTT法检测转染后细胞上清液中VEGF的生物活性。结果成功构建VEGF真核表达载体pcDNA3.1（-）/hVEGF165,其转染后的大鼠MSCs中VEGF表达水平明显增高,转染后细胞培养上清液具有促使内皮细胞增殖的生物活性。结论VEGF真核表达载体转染大鼠MSCs后能有效增加VEGF表达,并表现出较强的促内皮细胞增殖作用。     

血管内皮细胞生长因子真核表达质粒的构建及其在心肌细胞中的表达

目的 :构建血管内皮细胞生长因子 （ VEGF1 65）真核表达质粒 pc DNA3 .1（ -） /h VEGF1 65,并通过转染心肌细胞来验证其生物活性。方法 :应用 DNA重组方法 ,将编码 h VEGF1 65全长 c DNA克隆于真核表达载体 pc DNA3 .1（ -）中 ,构建 pc DNA3 .1（ -） /h VEGF1 65真核表达质粒 ;应用阳性脂质体介导的基因转染技术 ,将真核表达质粒 pc D-NA3 .1（ -） /h VEGF1 65瞬时转染培养的大鼠心肌细胞中 ;采用 RT-PCR,ELISA,Western blot及免疫组化染色等方法检测 VEGF1 65基因在心肌细胞中的表达情况 ;应用 MTT法检测转染后细胞上清液中 VEGF1 65的生物活性。结果 :将构建好的真核表达质粒 pc DNA3 .1（ -） /h VEGF1 65转染心肌细胞后 ,VEGF m RNA及蛋白表达水平明显增高 ,转染后的心肌细胞培养上清液具有促使内皮细胞增殖的生物活性。结论 :成功构建了真核表达质粒 pc DNA3 .1（ -） /h VEGF1 65,其转染心肌细胞后可获得较高水平 VEGF蛋白的表达 ,所表达出 VEGF蛋白具有生物学活性     

重组腺相关病毒介导人血管内皮生长因子165基因在培养大鼠心肌细胞中的表达

目的探讨2型腺相关病毒载体介导的人血管内皮生长因子165基因在离体心肌细胞中的表达及表达产物的生物活性。方法构建携带人血管内皮生长因子的2型腺相关病毒载体(rAAV-2/hVEGF165),感染大鼠原代心肌细胞,采用逆转录聚合酶链反应、免疫印迹法和酶联免疫吸附测定等方法检测心肌细胞人血管内皮生长因子165的表达,应用MTT法检测转染后细胞上清液中血管内皮生长因子165的生物学活性。结果逆转录聚合酶链反应检测结果发现感染的心肌细胞可表达人血管内皮生长因子165 mRNA;免疫印迹法检测结果表明感染的心肌细胞中有人血管内皮生长因子165,酶联免疫吸附测定法检测到血管内皮生长因子蛋白分泌水平为546.5±15.6pg/L,未转染组未检测到血管内皮生长因子蛋白的分泌;还发现感染的心肌细胞上清具有明显的促人内皮细胞增殖作用。结论2型腺相关病毒载体介导的人血管内皮生长因子165可有效转染大鼠心肌细胞,且表达产物具有促内皮细胞增殖作用。     

血管内皮生长因子真核表达载体的构建及其在培养鼠心肌细胞中的表达

目的　构建血管内皮生长因子 (VEGF1 6 5)真核表达载体 ,并检测其在鼠心肌细胞中的表达。方法　应用DNA重组方法 ,将编码hVEGF1 6 5全长cDNA克隆于真核表达载体pCR3中 ,构建pCR3.hVEGF1 6 5真核表达载体 ,使用脂质体包裹的方法将真核表达载体pCR3.hVEGF1 6 5转染至培养鼠心肌细胞中 ,采用逆转录聚合酶链式反应 (RT PCR)、Southernblot、免疫组织化学染色、酶联免疫吸附测定法检测VEGF1 6 5基因在心肌细胞中的表达和分泌。结果　将构建好的真核表达载体pCR3.hVEGF1 6 5转染心肌细胞后 ,VEGFmRNA及蛋白水平明显增高。结论　成功构建了真核表达载体pCR3.hVEGF1 6 5,其转染心肌细胞后能够获得较高水平的VEGF蛋白。     

腺相关病毒介导的血管内皮生长因子基因与骨髓间充质干细胞联合治疗大鼠肢体缺血的研究

目的 探讨腺相关病毒(rAAV)介导的人血管内皮生长因子(VEGF)165基因转染大鼠骨髓间充质干细胞(MSC)移植对血管新生的影响.比较单纯干细胞移植与联合基因治疗的疗效.方法 全骨髓培养法提取培养MSC;rAAV-VEGF165转染MSC中,酶联免疫吸附试验(ELISA)及反转录-聚合酶链反应(RT-PCR)检测VEGF的表达;以近交系大鼠建立骨骼肌缺血模型,40只大鼠随机分为4组,每组10只.对照组注射磷酸盐缓冲液(PBS);干细胞组移植等量MSC,转染术后7 d组和转染术后10 d组分别于结扎7 d和10 d后的缺血区移植转染VEGF基因的MSC,移植6周后做Ⅷ因子染色检测血管新生情况.结果成功培养出MSC,免疫组化CD44阳性表达,CD34阴性表达;流式细胞术CD90阳性表达.在转染rAAV-VEGF165后转染组1、3、5、7、9 d上清液中VEGF165分泌水平分别为(131.98±6.00)、(263.96±4.58)、(540.85±5.97)、(208.98±5.06)、(174.45±5.00)ng/L,明显高于未转染组的(68.72±1.99)、(76.47±4.98)、(89.86±1.99)、(84.93±8.97)、(68.71±5.98)ng/L[t值分别为14.14、51.16、79.28、27.56、26.07,(均P＜0.05)],且5 d时达到高峰,此后表达开始下降.琼脂糖凝胶电泳可见在579 bp处见到高亮度条带,证明rAAV-VEGF165成功转染进MSC细胞中.转染后的生长曲线及细胞形态较未转染组无明显变化.Ⅷ因子染色示转染术后10 d组动物缺血区毛细血管密度[(9.35±2.72)条/视野]明显高于对照组[(1.05±0.50)条/视野]和干细胞组[(3.10±1.43)条/视野](均P＜0.01),较转染术后7 d组[(6.95±1.69)条/视野]亦有一定程度的升高(P＜0.05).结论 MSC有利于VEGF基因的稳定表达,可作为VEGF基因的良好细胞载体,且联合应用效果高于单独移植MSC,移植最佳时间为术后10 d.     

血管内皮生长因子基因转染骨髓间充质干细胞移植对肺气肿大鼠的疗效

目的：观察血管内皮生长因子（VEGF）基因转染大鼠骨髓间充质干细胞（MSCs）移植对肺气肿大鼠肺泡壁细胞的修复作用。方法：pcDNA3．1-hVEGF转染雄性Lewis大鼠MSCs。雌性Lewis大鼠随机分为4组：正常对照组、肺气肿组、单纯MSCs移植组,hVEGF移植组。观察MSCs移植28d后肺组织形态学变化,支气管肺泡灌洗液细胞分类计数,ELISA法检测VEGF含量。Y染色体荧光原位杂交（Y-FISH）示踪雄性大鼠MSCs在雌性肺气肿大鼠肺组织内的植入情况;采用TUNEL法检测肺泡壁细胞凋亡,免疫组化法检测Bcl-2蛋白的表达。结果：hVEGF移植组肺气肿改变较肺气肿组、单纯MSCs移植组减轻;支气管肺泡灌洗液炎性细胞数较后2组减少;肺组织VEGF含量较后2组增多;肺泡壁细胞凋亡指数明显低于后2组;Bcl-2染色阳性细胞百分比高于后2组;Y-FISH显示hVEGF移植组、单纯MSCs移植组的雌性大鼠肺组织中有Y染色体阳性的细胞。结论：真核表达载体pcDNA3．1hVEGF可以成功地在MSCs中表达,pcDNA3．1hVEGF转染MSCs移植能够减轻大鼠肺气肿样改变,其疗效优于单纯MSCs移植治疗。

Abstract：

Objective： To evaluate the effect of mesenchymal stem cells （MSCs） transfected with human vascular endothelial growth factor （VEGF） gene for rats with pulmonary emphysema. Methods： MSCs from male lewis rats were transfected with the pcDNA3. 1-hVEGF control vector. Female Lewis rats were randomly divided into four groups： normal control group, emphysema group, emphysema ＋ MSCs transplantation group, emphysema ＋ hVEGF-transfected MSCs transplantation group. Morphologie changes of the lung tissue were observed 28 Jays after treatment. The total cell number of bronchoalveolar lavage fluid were counted, and the content of VEGF was de tected by ELISA. The engraftment of male bone marrow MSCs in female recipient lung was determined by Y chromosome fluorescent in situ hybridization （Y-FISH）. The apoptosis of the lung cells was assessed by TUNEL stai ning. The expression of Bcl-2 were determined by immunohistochemical staining. Results： Emphysematous change in the emphysema ＋ hVEGF transfeeted MSCs transplantation group was improved compared with those in emphysema group and the emphysema ＋ MSCs transplantation group. The total cell number of bronchoalveolar lavage fluid was decreased in the emphysema ＋ hVEGF transfected MSCs transplantation group compared to the emphysema group and the emphysema ＋ MSCs transplantation group. The level of VEGF was higher in emphysema ＋ hVEGF transfected MSCs transplantation group compared with those of the emphysema group and the emphysema ＋ MSCs transplantation group. The apoptotic index of the alveolar wall cells in the emphysema ＋ hVEGF transfeeted MSCs transplantation group was less than that of the emphysema group and the emphysema ＋ MSCs transplantation group. The percentage of Bcl-2 positive cells in the emphysema ＋ hVEGF transfected MSCs transplantation group was significantly higher than that of the emphysema group and the emphysema ＋ MSCs transplantation group. Y chromo some positive cells were observed in the lungs of rats from the emphysema ＋ hVEGF transfected MSCs transplantation group and the emphysema ＋ MSCs transplantation group, Conclusions： The hVEGF gene could expressed in MSCs. Trans plantation of MSCs transfected with hVEGF gene can improve emphysematous changes than single cellular therapy.     

腺病毒介导的hVEGF165基因治疗对骨髓移植后骨髓造血干细胞恢复的影响及其意义

目的：探讨重组腺病毒Ad—EGFP／hVEGF165介导的血管内皮细胞生长因子在骨髓移植后小鼠体内的表达效率及对骨髓造血干细胞恢复的影响。方法：利用细菌内同源重组法快速构建复制缺陷型腺病毒Ad—EGFP／hVEGF165，经尾静脉注射给同基因骨髓移植BALB／c小鼠；在移植后不同时间，通过荧光显微镜、RT—PCR、免疫组化染色和ELISA方法检测外源基因在小鼠体内的表达；取移植后30d小鼠骨髓单个核细胞并计数，随后进行脾集落形成单位试验(CFU—S)以评价VEGF基因转移组小鼠骨髓造血干细胞数量恢复情况。结果：重组腺病毒AdEGFP／hVEGF165介导的VEGF基因转移广泛分布在骨髓移植小鼠心、肺、肝、脾、肾、小肠和骨髓组织；小鼠血浆中VEGF浓度高峰出现在移植后2d；接受重组腺病毒AdEGFP／hVEGF165基因干预治疗组小鼠骨髓单个核细胞计数及其形成的脾集落数量明显高于其他对照组。结论：腺病毒成功介导了hVEGF165基因在骨髓移植小鼠体内的稳定表达，明显促进骨髓移植小鼠骨髓造血干细胞数量的恢复．是骨髓单个核细胞数量增加的根本原因。     

重组腺相关病毒介导人血管内皮生长因子165基因在大鼠骨髓间充质干细胞中的表达

目的探讨以腺相关病毒(rAAV)为血管内皮细胞生长因子165基因(VEGIF165)载体,在体外转染大鼠骨髓间充质干细胞(MSCs),并研究其相关特性。方法 (1)全骨髓培养法提取培养MSCs,利用免疫组化法检测MSCs表面标志CD34、CD44;流式细胞分析法检测CD90。(2)rAAV-VEGF165转染MSCs,采用ELISA及PCR检测VEGF的表达,比较转染前后细胞的变化情况,观察VEGF165基因转染对MSCs的影响。结果 (1)成功培养出MSCs,CD44阳性表达,CD34阴性表达,CD90阳性表达。(2)在转染rAAV-VEGF165后转染组上清中VFGF165分泌水平明显高于未转染组(p<0.05),5 d时达到高峰,此后表达开始下降。琼脂糖凝胶电泳可见高亮度条带。表明rAAv-VEGF165成功转染进MSCs细胞中,绘制生长曲线,显示rAAV-VEGF165基因转染后对MSC生长无影响。结论rAAV-VEGF表达载体可有效感染MSCs,并在体外高效表达,为MSCs联合基因治疗提供了实验依据。     

Transfection of bone marrow mesenchymal stem cells using green fluorescence protein labeled hVEGF165 recombinant plasmid mediated by liposome

ObjectiveTo study the role of bone marrow mesenchymal stem cells (BMSCs) in construction of vascularized engineered tissue.MethodshVEGF165 was amplified via RT-PCR before recombinant with pShuttle- green fluorescence protein;green fluorescent protein (GFP)-CMV. Then the recombinant shuttle plasmid was transfected into BMSCs with Lipofectamine^TM 2000 for packaging and amplifying. hVEGF165 mRNA expression in BMSCs cells was tested. Results: The sequence of hVEGF165 in pShuttle-GFP-hVEGF165 plasmid was confirmed by double-enzyme cleavage method and sequencing. hVEGF165 was highly expressed in BMSCs.ConclusionsThe GFP/hVEGF165 recombinant plasmid vector was constructed successfully and expressed effectively in host cells, which may be helpful for discussing the possibility of the application of VEGF165-BMSCs in tissue engineering and ischemic disease cure.     

Construction of the Eukaryotic Expression Vector with EGFP and hVE GF121 Gene and its Expression in Rat Mesenchymal Stem Cells

Objectives To construct a recombinant plasmid carrying enhanced green fluorescent protein (EGFP) and human vascular endothelial growth factor (VEGF) 121 gene and detect its expression in rat mesenchymal stem cells (MSCs). Methods Human VEGF121 cDNA was amplified with polymerase chain reaction (PCR) from pCD/hVEGF121 and was inserted into the eukaryotic expression vector pEGFPC1. After being identified with PCR, double enzyme digestion and DNA sequencing. The recombinant plasmid pEGFP/hVEGF121 was transferred into rat MSCs with lipofectamine. The expression of EGFP/VEGF121 fusion protein were detected with fluorescence microscope and immunocytochemical staining respectively. Results The recombinant plasmid was confirmed with PCR, double enzyme digestion and DNA sequencing. The fluorescence microscope and immunocytochemical staining results showed that the EGFP and VEGF121 protein were expressed in MSCs 48h after transfection.Conclusions The recombinant plasmid carrying EGFP and human VEGF was successfully constructed and expressed positively in rat MSCs. It offers a promise tool for further research on differentiation of MSCs and VEGF gene therapy for ischemial cardiovascular disease.     

血管内皮生长因子基因转染骨髓间充质干细胞移植促进缺血心肌血管生成的研究

目的研究血管内皮生长因子(vascularendothelial growth factor,VEGF)基因转染骨髓间充质干细胞(mesenchymalstem cells,MSCs)移植对缺血心肌的血管生成作用。方法于2004年5月至2005年8月取第四军医大学西京医院分离、培养Wistar大鼠的MSCs,用真核表达载体pcDNA3.1(-)/hVEGF165转染MSCs。45只近交系Wistar大鼠随机均分为转染组(MSCs/VEGF组)、对照组(MSCs组)、无血清培养基组(DMEM组),结扎前降支建立急性心肌梗死模型后在梗死区边缘区行5×106细胞移植,DMEM组行等量培养基注射。细胞移植前行CM-DiI标记。移植1个月后行心脏B超测量射血分数值,组织化学染色评价新生血管密度。结果培养的MSCs呈典型贴壁生长成纤维样外观,pcDNA3.1(-)/hVEGF165能有效转染大鼠MSCs,移植1个月后MSCs/VEGF组较其余各组左室射血分数(LVEF),再生血管密度明显增加,差异均有显著性(P<0.01)。结论VEGF基因转染MSCs移植能显著促进缺血心肌血管再生,进而改善心脏功能。     

Inhibitory effect of antisense vascular endothelial growth factor 165 eukaryotic expression vector on proliferation of hepatocellular carcinoma cells

AIM: To construct antisense VEGF(165) eukaryotic expression vector PCDNA(3)-as-VEGF(165) and to study its expression and effect on the proliferation of hepatocarcinoma SMMC-7721 cells. METHODS: VEGF(165) cDNA was inserted into polylinker sites of eukaryotic expression vector PCDNA(3) to construct PCDNA(3)-as-VEGF(165). Then the vector was transferred into human hepatocarcinoma cell strain SMMC-7721 with cation lipofectamine 2000 mediated methods to evaluate the expression of VEGF protein and the inhibitory effect on the proliferation of hepatocarcinoma SMMC-7721 cells. RESULTS: The detection indicated the presence of VEGF cDNA in normally cultured SMMC-7721 cells by PCR. VEGF mRNA expression was notably decreased in SMMC-7721 cells by RT-PCR after PCDNA(3)-as-VEGF(165) transfection. The expression of VEGF protein was dramatically inhibited (142.01+/-7.95 vs 1 625.52+/-64.46 pg/ml(-1), P<0.01) 2 days after transfection, which correlated with the dose of PCDNA(3)-as-VEGF(165)5 gene. VEGF protein was most expressed in PCDNA(3) transferred SMMC-7721 cells but few in PCDNA(3)-as-VEGF(165) transferred cells by immunohistochemical staining. The apoptotic rate of hepatocarcinoma SMMC-7721 cells was significantly promoted (17.98+/-0.86% vs 4.86+/-0.27%, P<0.01) and the survival rate was notably decreased (80.99+/-3.20% vs 93.52+/-3.93%, P<0.05) due to antisense VEGF(165) by flow cytometry (FCM). The transfection of antisense VEGF(165) gene resulted in the inhibitory effect on the proliferation of hepatocarcinoma cells by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and the death of all hepatocarcinoma cells on day 6 after transfection. CONCLUSION: It is confirmed that antisense VEGF(165) can inhibit the expression of VEGF protein, interfere with the proliferation and induce the apoptosis of hepatocarcinoma cells in our study. Antisense VEGF(165) gene therapy may play an important role in the treatment of human hepatocarcinoma.     

丙型肝炎病毒核心蛋白对低氧诱导因子-1α和血管内皮生长因子表达的影响

目的 探讨HCV核心蛋白对低氧诱导因子1 α(HIF-1 α)和血管内皮生长因子(VEGF)表达的影响. 方法 将HCV核心蛋白基因的真核表达载体flag2B-core和HIF-1 αsiRNA转染Huh7.5.1细胞;采用RT-PCR和Western blot法分别检测HIF-1 α、VEGF在mRNA和蛋白水平的表达变化,采用酶联免疫吸附试验检测细胞上清液中VEGF的含量.对各组间数据进行t检验.结果 Huh7.5.1细胞转染flag2B-core后,HIF-1 α和VEGF的mRNA和蛋白表达水平升高,细胞上清液中VEGF含量明显高于对照组[(654.5±43.7) pg/ml与(365.9±26.8)pg/ml,t=653.1％,P＜ 0.01)];Huh7.5.1细胞共转染flag2B-core和HIF-1 α siRNA后,HIF-1 α和VEGF的mRNA和蛋白表达水平降低,细胞上清液VEGF含量明显低于对照组[(389.2±29.6) pg/ml与(768.8±47.3) pg/ml,t=1330.22,P＜0.01).结论 HCV核心蛋白能够上调HIF-1 α和VEGF的表达;HCV可能通过核心蛋白来调节HIF-1 α和VEGF的表达.     

重组大鼠GATA4-pEGFP基因在骨髓间充质干细胞的表达及意义

目的 体外获得表达重组大鼠GATA4-pEGFP基因的骨髓间充质干细胞(MSCs),为进一步研究后者在心肌梗死治疗中的作用奠定基础.方法 提取胎鼠心肌细胞总RNA,RT-PCR法扩增获得GATA4基因,将目的基因克隆到pEGFP-N3载体并获得重组后GATA4-pEGFP质粒,采用密度梯度离心法联合贴壁法分离骨髓单个核细胞并获得MSCs.将重组质粒GATA4-pEGFP以Lipo2000转染到大鼠MSCs,G418筛选2周,Western blot和荧光检测重组质粒在MSCs中的表达情况.结果 成功构建重组大鼠GATA4-pEGFP真核表达载体并转染入MSCs中,Western blot和荧光检测证实GATA4-pEGFP基因在MSCs中呈阳性表达.结论 成功建立表达大鼠GATA4-pEGFP基因的MSCs,此为利用组织工程学方法治疗心肌梗死的研究奠定了基础.     

Vascular endothelial growth factor is efficiently synthesized in spite of low transfection efficiency of pSG5VEGF plasmids in vascular smooth muscle cells

The limitation of lipotransfection with plasmid vectors is its low efficiency and the short-term expression of introduced genes. This is particularly important when the synthesis of high amounts of therapeutic products is required. However, growth factors with paracrine action overcome this problem. The aim of our study was to check whether the amounts of vascular endothelial growth factor (VEGF) generated after plasmid lipotransfection into vascular smooth muscle cells (VSMC) can be sufficient to stimulate endothelial cell proliferation. Two plasmids, pSG5-VEGF121 and pSG5-VEGF165, harboring human VEGF121 and VEGF165 isoforms were constructed and lipotransfected into COS-7 cells or to rat VSMC. The transfection efficiency, estimated by the expression of control, beta-galactosidase gene, was about 50% in COS-7 but rarely exceeded 5% in VSMC. However, despite this, the smooth muscle cells generated high amounts of VEGF protein, up to 3 ng/ml medium. The biological activity of this VEGF was confirmed by enhanced proliferation of human umbilical vein and coronary artery endothelial cells, stimulated with conditioned media of pSG5-VEGF transfected cells. Thus, the low transfection efficiency does not preclude the generation of high amounts of VEGF by VSMC. After reaching the maximum at about 48 h after transfection, the generation of VEGF decreased in the following days. Such a situation may be sufficient for the gene therapy of restenosis when the long-term expression of therapeutic gene(s) is not necessary. Thus, we suggest that the pSG5-VEGF121, and pSG5-VEGF165 plasmids can be used for therapeutic application.     

5-氮胞苷对培养兔骨髓基质细胞心房利钠肽表达的影响

目的研究5-氮胞苷(5-azacytidine,5-aza)对体外培养兔骨髓基质细胞中心肌特异性心房利钠肽(atrialnatriureticpolypeptide,ANP)表达的影响,探讨骨髓基质细胞向心肌样细胞分化的条件。方法体外分离培养兔骨髓基质细胞用不同浓度5-aza诱导培养,以RT-PCR方法测定诱导前后ANP的表达。结果正常培养兔骨髓基质细胞不表达ANP。经5-aza诱导并继续培养24h后,骨髓基质细胞表达ANP,在一定时间、浓度范围内ANP含量逐渐增加。结论5-aza诱导体外培养兔骨髓基质细胞表达心肌特异性ANP,与诱导时间及浓度呈正相关,提示可诱导兔骨髓基质细胞向心肌样细胞分化。     

Development of angiogenic cell and gene therapy by transplantation of umbilical cord blood with vascular endothelial growth factor gene.

Endothelial progenitor cells (EPCs) are present in the mononuclear cells (MNCs) of umbilical cord blood and peripheral blood. To establish the efficiency of angiogenic cell and gene therapies, we transfected the human vascular endothelial growth factor (hVEGF) gene into cord blood MNCs to enhance endothelialization. MNCs from cord blood and peripheral blood were isolated and transfected with pCR3 expressing hVEGF165 or GFP by the Hemagglutinating Virus of Japan (HVJ)-envelope and the cells were cultured in endothelium basal medium-2. The number of attached cells from cord blood was higher than that from peripheral blood. Attached cells expressed Flk-1, VE-cadherin, PECAM-1, CD34, and Tie-2. The increase in the number of attached cells was transient with the transfection of vascular endothelial growth factor (VEGF) gene early in the experimental period. Flt-1 mRNA was not expressed early in the culture period, but was expressed at 2 weeks after separation. VEGF gene transfer into MNCs at 12 days after separation, i.e., when Flt-1 mRNA was expressed continuously, increased the number of attached cells. We evaluated the effects of the transplantation of cord blood MNCs expressing the hVEGF gene on regional blood flow in an ischemic area in a rat model of chronic hindlimb ischemia. Blood flow was significantly improved in nude rats that received transplanted control MNCs. Transplantation of cord blood MNCs transfected with the hVEGF gene yielded greater improvements in blood flow. These results indicate that the hVEGF gene enhances endothelialization of EPCs, and that the transplantation of cord blood MNCs transfected with the VEGF gene may be feasible for the treatment of ischemic diseases as a type of angiogenic cell and gene therapy.     

间充质干细胞分化为心肌样细胞与P120连环蛋白mRNA表达

目的：研究5-氮杂胞苷（5-azacytidine，5-aza）诱导体外骨髓间充质干细胞（marrow measenchymal stem cells，MSCs）向心肌细胞发展的作用及其机制。方法：从Wistar大鼠骨髓中获得MSCs，培养传代后用不同浓度的5-aza诱导，倒置光显微镜和透射电镜观察诱导前后细胞形态变化；流式细胞术检测细胞周期改变；MTT法检测5-aza对MSCs生长的影响；免疫细胞化学法检测肌红蛋白、结蛋白和肌动蛋白的表达；RT-PCR检测P120连环蛋白1A mRNA的表达。结果：5-aza对MSCs有抑制增殖的作用（P〈0．05）；在光镜和透射电镜下可见有心肌样细胞的形态变化；免疫细胞化学检测结果表明，MSCs的经5-aza诱导14d，肌红蛋白、结蛋白和肌动蛋白的表达均较对照组显著增高（P〈0．01）；PT—PCR结果表明P120连环蛋白mRNA表达明显，而对照组未见表达。结论：MSCs可在体外被5-aza诱导分化成心肌样细胞，这可能与P120连环蛋白1A mRNA表达有关。