In vitro effect of p21^WAF-1／CIPI gene on growth of human glioma cells mediated by EGFR targeted non-viral vector GE7 system

To construct the EGFR targeted non-viral vector GE7 system and explore the in vitro effect of p21^WAF-1/CIP1 gene on growth of human glioma cells mediated by the GE7 system. Methods: The EGFR targeted non-vi-ral vector GET gene delivery system was constructed. The malignant human glioma cell llne U251MG was transfected in vitro with β-galactosidase gene( reporter gene) and p21^WAF-1/CIP1 gene (therapeutic gene) using the GET system. By means of X-gal staining, MTS and FACS, the transfection efficiency of exogenous gene and apoptosis rate of tumor cells were examined. The expression of p21^WAF-1/CIP1 gene in transfected U251MG cell was examined by immunohistochemitry staining. Results: The highest transfer rate of exogenous gene was 70%. After transfection with p21^WAF-l/CIP1 gene,the expression of WAF-1 increased remarkably and steadily; the growth of U251MG cells were inhibited evidently.FACS examination showed G1 arrest. The average apoptosis rate was 25.2%. Conclusion: GE7 system has the ability to transfer exogenous gene to targeted cells efficiently, and expression of p21^WAF-l/CIP1 gene can induce apoptosis of glio-ma cell and inhibit its growth.     

Gene transfer of a β2-adrenergic receptor kinase inhibitor up-regulates the level of β2-adrenergic receptor and cAMP in the asthmatic murine lung

Objective: To investigate the effects of gene transfer of a β-adrenergic receptor(β-AR) kinase inhibitor(β ARKct)on pulmonary β2-adrenergic receptor and cAMP following β2-AR agonist treatment in asthmatic mice, and to analyze the relationship between the routes of gene delivery and the changes of β2AR and cAMP. Methods: BALB/c mice were sensitized and challenged by ovalbumin to establish the asthmatic model treated with βAR agonist ( salbutamol injected intramuscularly). The plasmid with the expression of βARKct was constructed and βARKct gene transfer was performed through intravenous injection or intratracheal instillation in asthmatic mice.The gene expression was measured with Western blot analysis, and the changes of pulmonary β-AR and cAMP evaluated by Radioimmunoassay. Results: The expression of tranfered βARKct gene was detectable in lungs and it was expressed more in the lungs of the mice receiving intratracheally plasmid than those receiving intravenously. The levels of βAR and cAMP were upregulated after using plasmid-βARKct to the asthmatic mice treated with β AR agonist. Conclusion: Our results indicated that there were down-regulation of βAR and cAMP in asthmatic mice treated with βAR agonist. Gene transfer of βARKct could inhibit the extent of the down-regulation of βAR and cAMP. The route of gene delivery could also affect the degree of up-regulation of βAR and cAMP. Gene transfer βARKct may provide a novel approach to the therapeutic strategy for asthma.     

An experimental study of intravascular stent in abdominal aorta of atherosclerotic miniature pigs.

To study the effects of nitinol alloy stent in the treatment of atherosclerotic arterial stenosis, eight miniature pigs were subject to abdominal aortic balloon denudation and high-fatty food. Then 8 nitinol alloy stents were implanted into each abdominal aortas of pigs. The pigs were equally divided into two groups. One group was given captopril (3 mg / kg / d). All animals were sacrified) for pathological examination 6 to 10 months after stent implantation. The degree of arterial intima proliferation in the areas of stent implantation not significantly different from that of areas of balloon denudation alone; the atherosclerotic lesions were found at the arterial surface of stent implantation sites. The intima layer was rich in smooth muscle cells, with atherosclerotic plaque formed around the stent wire. On the other hand, significant decrease in arterial intima proliferation was found in group Ⅱ with no atherosclerotic plaque. The arterial stenosis resulting from atherosclerotic lesion could not be     

Gene transfer of a β2-adrenergic receptor kinase inhibitor up-regulates the level of β2-adrenergic receptor and cAMP in the asthmatic murine lung

Objective： To investigate the effects of gene transfer of a β-adrenergic receptor（β-AR） kinase inhibitor（β ARIct） on pulmonary β2-adrenergic receptor and cAMP following β2-AR agonist treatment in asthmatic mice, and to analyze the relationship between the routes of gene delivery and the changes of β2AR and cAMP. Methods： BALB/c mice were sensitized and challenged by ovalbumin to establish the asthmatic model treated with βAR agonist （salbutamol injected intramuscularly）. The plasmid with the expression of βARKct was constructed and βARKct gene transfer was performed through intravenous injection or intratracheal instillation in asthmatic mice. The gene expression was measured with Western blot analysis, and the changes of pulmonary β-AR and cAMP evaluated by Radioimmunoassay. Results： The expression of tranfered βARKct gene was detectable in lungs and it was expressed more in the lungs of the mice receiving intratracheally plasmid than those receiving intravenously. The levels of βAR and cAMP were upregulated after using plasmid-βARKct to the asthmatic mice treated with βAR agonist. Conclusion： Our results indicated that there were down-regulation of βAR and cAMP in asthmatic mice treated with βAR agonist. Gene transfer of βARKct could inhibit the extent of the down-regulation of βAR and cAMP. The route of gene delivery could also affect the degree of up-regulation of βAR and cAMP. Gene transfer βARKct may provide a novel approach to the therapeutic strategy for asthma.     

Use of PEI-coated Magnetic Iron Oxide Nanoparticles as Gene Vectors

Summary: To evaluate the feasibility of using polyethyleneimine (PEI) coated magnetic iron oxide nanoparticles (polyMAG-1000) as gerle vectors. The surface characteristics of the nanoparticles were observed with scanning electron microscopy. The ability of the nanoparticles to combine with and protect DNA was investigated at different PH values after polyMAG-1000 and DNA were combined in different ratios. The nanoparticles were tested as gene vectors with in vitro transfection models. Under the scanning electron microscope the nanoparticles were about 100 nm in diameter.The nanoparticles could bind and condense DNA under acid, neutral and alkaline conditions, and they could transfer genes into cells and express green fluorescent proteins (GFP). The transfection efficiency was highest (51%) when the ratio of nanoparticles to DNA was 1 : 1 (v:w). In that ratio, the difference in transfection efficiency was marked depending on whether a magnetic field was present or not: about 10 % when it was absent but 51% when it was present. The magnetic iron oxide nanoparticles coated with PEI may potentially be used as gene vectors.     

Effects and mechanisms of non-restrictive external stent for prevention of vein graft restenosis in a rabbit model

Background Among various treatments preventing vein graft restenosis, external stent is receiving more and more attention. This study aimed to investigate the effect of non-restrictive external stent on the prevention of vein graft restenosis and the potential mechanisms of platelet-derived growth factor （PDGF） in the process of restenosis.Methods Thirty-six ＂New Zealand white rabbits＂ were randomly divided into two groups, stented group （group S） and control group （non-stented group, group NS）. Each rabbit underwent a reversed autologous external jugular vein into common carotid artery bypass grafting. In group S, the vein grafts were surrounded by a non restrictive stent which was 6 mm in diameter （a kind of Dacron vascular prosthesis）; and in group NS, there was no stent to support the vein grafts.The grafts were harvested at the first week （1W）, second week （2W） and fourth week （4W） after surgery respectively. The dimensions （including the thickness and area of the intima and media, luminal area） were measured by computer-aided image analysis system, and the intimal hyperplasia ratio was defined as the percentage of the area enclosed by the internal elastic lamina occupied by the intima.Results At 1W, the difference of the thickness and area of the intima between groups S and NS was not significant （P 〉0.05）; at 2W and 4W, the thickness and area of the intima and the intimal hyperplasia ratio in group S were less significant than those in group NS （P 〈0.05）; from 1W to 4W, the thickness and area of the media in group S were smaller than those in group NS （P〈0.05）. Immunocytochemistry staining of PDGF-B showed that the percentage of positive cells of intima in both two groups was peaked at 2W, and a significantly smaller percentage was detected in group S compared with that in group NS at 2W and 4W （P 〈0.05）; the percentage of PDGF-B positive cells of media in both two groups was also peaked at 2W, and that in group S was smaller than that in group NS from 1W to 4W （P 〈0.05）; and the percentage of PDGF-B positive cells of adventitia in group S was peaked at 4W, whereas the percentage of adventitia in group NS peaked at 2W, and the percentage of adventitia in group S was greater than in group NS at 4W （P 〈0.05）.Conclusions Non-restrictive external stenting inhibits the hyperplasia of the intima and media of the vein grafts and reduces the thickness and area of the intima and media; Non-restrictive external stenting inhibits the synthesis of PDGF and changes its distribution, and then inhibits the hyperplasia of the intima.     

Expression of Transforming Growth Factor β1 in Mesenchymal Stem Cells: Potential Utility in Molecular Tissue Engineering for Osteochondral Repair

Summary: The feasibility of using gene therapy to treat full-thickness articular cartilage defects was investigated with respect to the transfection and expression of exogenous transforming growth factor (TGF)-β1 genes in bone marrow-derived mesenchymal stem cells (MSCs) in vitro. The full-length rat TGF-β1 cDNA was transfected to MSCs mediated by lipofectamine and then selected with G418,a synthetic neomycin analog. The transient and stable expression of TGF-β1 by MSCs was detected by using immunohistochemical staining. The lipofectamine-mediated gene therapy efficiently trans fected MSCs in vitro with the TGF-β1 gene causing a marked up-regulation in TGF-β1 expression as compared with the vector-transfected control groups, and the increased expression persisted for at least 4 weeks after selected with G418. It was suggested that bone marrow-derived MSCs were sus ceptible to in vitro lipofectamine mediated TGF-β1 gene transfer and that transgene expression persist-ed for at least 4 weeks. Having successfully combined the existing techniques of tissue engineering with the novel possibilities offered by modern gene transfer technology, an innovative concept, I.e.molecular tissue engineering, are put forward for the first time. As a new branch of tissue engineer-ing, it represents both a new area and an important trend in research. Using this technique, we have a new powerful tool with which: (1) to modify the functional biology of articular tissue repair along defined pathways of growth and differentiation and (2) to affect a better repair of full-thickness artic ular cartilage defects that occur as a result of injury and osteoarthritis.     

Inhibitory effect of adenoviral vector-mediated AT2R gene transfection on neointimal hyperplasia

Objective： To investigate the effect of adenoviral vector-mediated AT2R gene transfection on neointimal hyperplasia after rat carotid artery balloon injury. Methods ：AT2R gene was transferred into rat carotid arteries by recombinant adenovirus pAd-AT2R after the establishment of rat carotid balloon injury restenosis model. The arteries were harvested on the 14th day after gene transfer. The efficiency of transgene delivery was measured by the expression of adenovirus-encoding green fluorescent protein （GFP） under fluorescent microscope. The expression of AT2R and PCNA （proliferating cell nuclear antigen） was evaluated by RT-PCR, immunocytochemistry, immunofluorescence staining, confocal microscopy, respectively. The ratio of intimal to medial area （I/M） was quantified with images and determined by an image analysis system. Results, GFP-positive area in adventitia, media and the forming neointima was about 40%. Adenoviral delivery of rat AT2R gene up-regulated AT2R expression in balloon-injured rat carotid and reduced PCNA expression and I/M significantly in neointima（P〈0.01）. Double immunofluorescence labeling of AT2R and PCNA also showed that AT2R gene transfer inhibited VSMCs proliferation in neointima. Conclusion： AT2R gene transfer may be a novel promising therapy to limit neointimal hyperplasia.     

Ultrasound and Microbubbles： Their Functions in Gene Transfer In Vitro

To examine the role of ultrasound in gene delivery in vitro, three cells lines were exposed to the low-frequency ultrasound of varying intensities and for different durations to evaluate their effect on gene transfection and cell viability of the cells. Microbubble （MB）, Optison （10%）, was also used to observe the role of the microbubbles in gene transfection. The results demonstrated that as the ultrasound intensity and the exposure time increased, the gene transfer rate increased and the cell viability decreased, but at high energy intensities, the cell viability decreased dramatically, which caused the transfer rate to decrease. The most efficient ultrasound intensity for inducing gene transfer was 1 W/cm^2 with duration being 20 s. At the same energy intensity, higher ultrasound intensity could achieve maximal gene transfer rate earlier. Microbubbles could increase ultrasound-induced cell gene transfer rate by about 2 to 3 times mainly at lower energy intensities. Moreover, microbubbles could raise the maximum gene transfer rate mediated by ultrasound. It is concluded that the low-frequency ultrasound can induce cell gene transfer and the cell gene transfer rate and viability are correlated with not only the ultrasound energy intensity but also the ultrasound intensity, the higher ultrasound intensity achieves its maximal transfer rate more quickly and the ultrasound intensity that can induce optimal gene transfer is 1 W/cm^2 with duration being 20 s, and microbubbles can significantly increase the maximal gene transfer rate in vitro.     

转染人诱导型一氧化氮合酶基因对鼠颈动脉新生内膜增生的抑制作用

目的 研究腺病毒介导的人诱导型NO合酶基因经内膜转染对球囊损伤后鼠颈动脉新生内膜的抑制作用及对血一氧化氮(NO)浓度的影响。方法 建立鼠颈动脉球囊损伤模型，将LacZ重组腺病毒(AdLacZ)和人诱导型一氧化氮合酶基因重组腺病毒(Adinos)在体内分别转染损伤动脉节段，以HE染色、计算机图像处理方法观察转染动脉节段新生内膜增生情况；用硝酸还原酶法测定动脉血中NO浓度。结果 与AdLacZ转染组及未转染组比较，Adinos基因转染组鼠颈动脉血中NO浓度在转染后7天和14天都显著提高；转染4周后未转染组、AdLacZ转染组、Adinos基因转染组的新生内膜面积分别为0．78mm^2、0．75mm^2及0．17mm^2；管腔狭窄率分别为74．9％、79．5％及24。6％。结论 转染Adinos基因可显著提高NO浓度并显著抑制损伤动脉节段新生内膜增生及管腔狭窄。     

Gene transfer and expression in rat anastomotic artery in vivo using adenoviral vector

Objective To observe the efficiency and time course of gene expression and the safety of a denoviral vector mediated gene transfer in vivo.Methods After soaking soluble stents in a high concentration of glucose solution contain ing Adv(5)-CMV (cytomegalovirus) (control group) or Adv(5)-CMV/LacZ (treatment group) for 30 minutes, the stents were inserted into the lumina of cut rat caro tid arteries and end-to-end anastomoses of the cut carotid were performed with standard microvascular surgical techniques. On days 2, 7, 14, 28, 60 and 90 af ter gene transfer, anastomotic arteries of the two groups were observed. On da ys 7 and 14, the ascending aortas, hearts, brains, livers, lungs, spleens and ki dneys of the treatment group were observed. All samples were analyzed for the presence of β-galactosidase activity and histochemical staining.Results β-galactosidase activity was not detected in the carotid arteries of the contr ol group and organs not directly exposed to adenoviral vector of the treatment g roup. The amount of β-galactosidase activity(×10(-3) U/g tissue) in t he treatment group on the 2nd, 7th, 14th, 28th, 60th and 90th day after gene tra nsfer was 3.87, 11.38, 9.8, 6.43, 3.18 and 2.43, respectively. Microscopi c examination of sections from vessels of the control group and from the aortas, hearts, brains, livers, lungs, spleens or kidneys of the treatment group reveal ed no X-gal staining. Microscopic examination of carotid arteries of the treat ment group revealed blue-staining in all anastomotic arteries and in all layers of the arterial wall observed on days 7 and 14 after gene transfer.Conclusion Adenoviral vector can effectively infect blood vessels in vivo. After adenovira l vector mediated direct gene transfer into anastomotic rat carotid arteries, re combinant gene expression began on day 2, peaked between days 7 and 14, prominen tly declined after day 28, and persisted at low levels more than three months. A recombinant gene could be delivered to a specific site by direct gene transfer in vivo by adenoviral vector infection.     

腺病毒载体转染大鼠颈动脉的实验研究

目的观察腺病毒载体转染大鼠颈动脉的有效性和外源性基因表达的时间过程。方法用ＡｄＶ５－ＣＭＶ质粒（对照组）或Ａｄｖ５－ＣＭＶ／ＬａｃＺ质粒（治疗组）转染大鼠颈动脉３０分钟。术后２、７、１４、２８、６０及９０天取被转染的颈动脉,行β－半乳糖苷酶活性测定和组织化学染色。结果对照组所有颈动脉均无β－半乳糖苷酶活性,治疗组术后２天颈动脉即有β－半乳糖苷酶的表达,７～１４天为表达高峰期,２８天后表达量明显减少,但可持续表达３个月之久。治疗组术后２、７、１４、２８、６０及９０天每条颈动脉均可见蓝染,其中术后７及１４天每条颈动脉横切面的全周均有蓝染,血管壁内层、中层的大部分细胞被染成蓝色。对照组所有动脉均未见蓝染。结论腺病毒载体能高效转染大鼠在体颈动脉。转染后,外源性基因的高水平表达只能维持１个月左右。     

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.     

JAK2-STAT3信号通路在白介素-1β经动脉外膜给药致平滑肌细胞增殖迁移中的作用

目的研究白细胞介素-1β经血管外膜给药导致动脉平滑肌细胞发生的改变及其与JAK2-STAT3信号通路的关系,明确JAK2-STAT3信号通路在血管增殖性病变中的作用。方法 6～8周龄SD雄性大鼠24只,分离左侧颈总动脉,实验组(n=18)血管外膜包裹含白介素-1β2.5μg的琼脂缓释悬液,对照组(n=6)包裹不含白介素的琼脂悬液,术后2、8、24、48 h,1、2周分别处死实验组大鼠3只,对照组1只,血管标本经切片HE染色观察形态,Western blot法检测JAK2、STAT3、磷酸化JAK2以及磷酸化STAT3的表达,免疫组化标记定位磷酸化JAK2及磷酸化STAT3;另取SD雄性大鼠9只,分离两侧颈总动脉,左侧滴加JAK2抑制剂AG490缓释凝胶,右侧滴加等量空白凝胶后两侧均包裹等量白介素-1β,术后8、48 h,1周处死动物分别行HE染色及Western blot检测。结果白介素-1β包裹血管外膜后出现血管平滑肌细胞的增殖、迁移,通道蛋白JAK2、STAT3在不同时间点出现不同程度的磷酸化,经Western blot检测并行灰度分析,p-JAK2相对灰度值对照组(0.337±0.216),8 h组(1.764±0.513),1周组(0.451±0.229);p-STAT3相对灰度值对照组(0.125±0.870),24 h组(1.909±0.309),2周组(0.448±0.516),各组间有明显差异(P<0.05)。加用抑制剂后,8 h组p-JAK2相对灰度值实验侧(0.085±0.031),对照侧(1.416±0.468),48 h组p-STAT3相对灰度值实验侧(0.460±0.065),对照侧(2.425±0.638),提示JAK2、STAT3的磷酸化水平被明显抑制(P<0.05),平滑肌细胞变化程度下降。结论炎性因子白细胞介素-1β经动脉外膜给药可致动脉平滑肌细胞增殖、迁移,这种改变与JAK2-STAT3信号通路有直接关系。     

腺病毒介导的碱性成纤维细胞生长因子对人骨关节炎软骨细胞的作用

目的:探讨腺病毒介导的人碱性成纤维细胞生长因子(bFGF)对体外培养的人骨关节炎(OA)软骨细胞的转染及其作用。方法:人OA软骨细胞分为3组:OA对照组、绿色荧光蛋白(EGFP)对照组及bFGF转染组。采用含bFGF的腺病毒载体转染人OA软骨细胞,48 h后通过流式细胞术分析腺病毒转染软骨细胞的效率,绘制转染效率曲线。6 d后检测培养基中bFGF的浓度及软骨细胞增殖;观察软骨细胞蛋白多糖及Ⅱ型胶原的表达。结果:腺病毒介导的bFGF可高效转染人OA软骨细胞并在细胞外表达。与OA对照组相比,bFGF转染后可明显促进软骨细胞的增殖(P<0.05);同时增加了软骨细胞蛋白多糖和Ⅱ型胶原的生物合成(P<0.05)。结论:腺病毒介导的bFGF可促进OA软骨细增殖,增强细胞基质的合成,对软骨细胞表型的维持具有重要作用。     

腺病毒载体介导的bFGF基因体外转染大鼠平滑肌细胞的实验研究

目的观察携带bFGF基因的重组腺病毒体外转染平滑肌细胞的效率及转染后目的基因的表达。方法应用磷酸钙共沉淀法分别构建携带bFGF基因和大肠杆菌LacZ报道基因的重组腺病毒载体Ad．bFGF和Ad．LacZ，并以Ad．bFGF（组Ⅰ）、Ad．LacZ（组Ⅱ）、PBS（组Ⅲ，对照组）转染体外培养的大鼠平滑肌细胞（SMCs）。X—gal染色检测腺病毒载体的转染效率，噻唑蓝（MTT）检测各组SMCs的增殖情况，酶联免疫吸附（ELISA）检测各组培养液中bFGF蛋白的浓度。结果当MOI值为100时，X-gal核蓝染细胞比率达95％以上；组ⅠSMCs的增殖水平显著高于组Ⅱ和组Ⅲ（P〈0．01）；ELISA方法检测，在转染后第1天组Ⅰ培养波中即有bFGF蛋白的分泌表达，第3天达峰值后分泌量逐渐下降，第8天仍能检测到少量分泌，而组Ⅱ和组Ⅲ培养液中均未检测到bFGF蛋白。结论成功地将所构建的Ad. bFGF转染体外培养的SMCs，并在培养液中检测到目的基因的蛋白表达。     

腺病毒介导的HSP70基因转染对乳鼠心肌细胞缺氧/复氧损伤的保护作用

目的:研究热休克蛋白70(HSP70)基因转染对体外培养的乳鼠心肌细胞缺氧/复氧损伤的保护作用。方法:体外原代培养乳鼠心肌细胞,以携带增强型绿色荧光蛋白(EGFP)基因的腺病毒载体(Ad.EGFP)按不同感染倍数(MOI)感染体外心肌细胞,通过荧光显微镜、流式细胞仪观察所构建腺病毒的感染力和安全性;应用含有人HSP70基因的重组腺病毒(Ad.HSP70)进行体外感染,采用ELISA法、Western印迹法及免疫组化染色法检测HSP70基因在心肌细胞中的表达情况。利用体外心肌细胞缺氧/复氧损伤模型,研究HSP70基因转染对心肌细胞的保护作用。结果:原代培养获得高纯度的乳鼠心肌细胞,随着MOI值升高,Ad.EGFP的感染效率和基因表达增强,在MOI值为50时,Ad.EGFP感染心肌细胞的效率高于90%,在MOI值为200时,未见心肌细胞的生长明显受抑;ELISA法、Western印迹法证实转染的心肌细胞在正常生理状态下,可高水平表达HSP70。免疫组化染色法结果显示,表达的HSP70主要分布于心肌细胞的胞质和胞核中;利用体外的缺氧/复氧损伤模拟在体的缺血/再灌注损伤,结果显示Ad.HSP70感染组的细胞活力、MT...