β-catenin对骨形态发生蛋白9诱导间充质干细胞成骨分化的影响

目的探讨经典Wnt信号通路关键节点β-catenin对骨形态发生蛋白9(bone morphogenetic protein 9,BMP9)诱导间充质干细胞(mesenchymal stem cells,MSCs)成骨分化的影响。方法用重组腺病毒介导BMP9在C3H10T1/2细胞中过表达,联用β-catenin重组腺病毒上调β-catenin的表达,并通过RNA干扰抑制β-catenin的表达。分析C3H10T1/2细胞碱性磷酸酶(alkaline phosphatase,ALP)活性的变化;RT-PCR检测细胞成骨分化相关基因骨桥蛋白(osteopontin,OPN)和骨钙蛋白(osteocalcin,OC)基因mRNA的转录水平;茜素红S染色检测细胞的钙盐沉积。结果 BMP9单独作用能诱导C3H10T1/2细胞向成骨方向分化,并增强细胞ALP活性;单独的β-catenin无成骨诱导作用,但可剂量依赖性地增强BMP9诱导的C3H10T1/2细胞的ALP活性,并促进BMP9诱导的细胞OPN和OC基因mRNA的转录水平及钙盐沉积;抑制β-catenin表达可显著降低BMP9诱导的C3H1OT1/2细胞的ALP活性(P0.05),下调OPN和OC基因mRNA的转录水平,并抑制钙盐沉积。结论经典Wnt信号通路可能通过β-catenin协同BMP9诱导C3H10T1/2细胞成骨分化,且BMP9诱导的成骨分化可能需要通过Wnt/β-catenin途径来实现。     

cAMP-PKA-CREB信号通路在骨形态发生蛋白9诱导小鼠间充质干细胞成骨分化中的作用

目的探讨cAMP-PKA-CREB信号通路在骨形态发生蛋白9(bone morphogenetic protein 9,BMP9)诱导小鼠间充质干细胞(mesenchymal stem cells,MSCs)C3H10T1/2成骨分化过程中的作用及其机制。方法将C3H10T1/2细胞分别加入不同浓度的cAMP-PKA-CREB信号通路抑制剂H89(1、2.5、5和10μmol/L),检测其对碱性磷酸酶(alkaline phosphatase,ALP)活性的影响;通过ALP定量和钙盐沉积试验分别检测H89对BMP9诱导C3H10T1/2细胞早期和晚期成骨分化的影响;经Western blot法检测H89对C3H10T1/2细胞中磷酸化CREB、骨钙素(Osteocalcin,OCN)和成骨关键转录因子Runx2表达水平的影响;通过Wentern blot及荧光素酶活性的检测,观察H89对经典信号通路BMPs-smad1/5/8的影响。结果随着H89浓度的增加,对BMP9诱导的C3H10T1/2细胞ALP的抑制作用明显增强(P0.05),且呈剂量依赖性;ALP定量和钙盐沉积试验结果表明,H89可明显抑制BMP9诱导的C3H10T1/2细胞早期及晚期成骨分化;H89可显著抑制BMP9诱导的C3H10T1/2细胞中磷酸化CREB、OCN及Runx2蛋白的表达(P0.05),与AdBMP9组比较,H89对经典BMPs-smad1/5/8信号通路无明显影响(P0.05)。结论阻断cAMP-PKA-CREB信号通路可抑制BMP9诱导的MSCs C3H10T1/2的成骨分化,为BMP9的临床应用奠定了理论基础。     

人肝细胞生长因子基因真核表达质粒的构建及其在人骨髓间充质干细胞中的表达

目的构建人肝细胞生长因子(Human hepatocyte growth factor,hHGF)真核表达质粒,并检测其在人骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BMSCs)中的表达及其对细胞生长的影响。方法采用密度梯度法从人骨髓中分离BMSCs,流式细胞术检测细胞表型,成脂及成骨诱导其分化。PCR扩增hHGF基因,定向克隆至pEGFP-N1载体中,构建重组表达质粒pEGFP-N1-hHGF,通过电穿孔法转染BMSCs,荧光显微镜下观察增强型绿色荧光蛋白的表达,RT-PCR及Western blot法检测hHGF基因mRNA的转录及蛋白的表达,MTT法检测hHGF对BMSCs增殖活力的影响。结果 BMSCs高表达CD29和CD44,不表达CD34和CD45;BMSCs在体外有向成脂及成骨细胞诱导分化的能力。酶切及基因测序证实,重组表达质粒pEGFP-N1-hHGF构建正确;转染后48 h观察到转染细胞中有绿色荧光蛋白表达;RT-PCR法和Western blot检测到hHGF基因在BMSCs中表达;转染hHGF基因的BMSCs增殖活力明显高于空白对照组和空载体转染组(P<0.05)。结论成功构建了hHGF基因真核表达质粒,转染人BMSCs后获得表达,表达的hHGF可促进BMSCs增殖。     

大鼠骨髓间充质干细胞向肝样细胞的定向诱导分化

目的 探讨肝细胞生长因子(Hepatocyte growth factor,HGF)和碱性成纤维细胞生长因子(Basic fibroblast growthfactor,bFGF)诱导大鼠骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BM-MSCs)分化为肝样细胞的可行性。方法取SD大鼠股骨骨髓,直接贴壁法分离纯化BM-MSCs,并体外传代,流式细胞术和成骨诱导对其进行鉴定。取第3代BM-MSCs,分为2组:实验组用HGF(20 ng/ml)和bFGF(10 ng/ml)进行诱导,阴性对照组不加诱导剂,倒置显微镜下观察细胞形态变化;RT-PCR法检测诱导后细胞甲胎蛋白(Alpha fetoprotein,AFP)和白蛋白(Albumin,ALB)基因mRNA的转录水平;免疫细胞化学染色法检测诱导后细胞的AFP和ALB蛋白的表达。结果第3代BM-MSCs表型标志和功能特性均符合MSCs的特点。BM-MSCs经HGF和bFGF诱导后呈肝样细胞形态。实验组细胞可检测出AFP和ALB基因mRNA的表达。实验组细胞诱导后第7天,AFP蛋白开始表达,第14天时表达降低,第21天时不表达;ALB于诱导后第14天出现表达,并随诱导时间的延长表达逐渐增加。结论 HGF和bFGF具有体外诱导BM-MSCs向肝样细胞分化的作用。     

重组人骨形态发生蛋白-2的制备及成骨活性表征

骨形态发生蛋白-2(BMP-2)是重要的骨诱导生长因子,是提高骨修复材料活性和临床骨修复效果的有效手段和关键物质。由于BMP-2在体内含量低,依靠从动物体内提取难以满足临床需求。本文研究满足临床需求的BMP-2的制备方法,并评价其生物活性。采用密码子优化方法,并通过进一步更换其中部分核苷酸编码,得到优化的hBMP-2基因的DNA序列,制备大肠杆菌rhBMP-2菌株,通过发酵及工艺优化,获得BMP包涵体,经分离纯化与复性,制备出高纯度的rhBMP-2。测定C2C12细胞的碱性磷酸酶(ALP)活性来表征单倍体和二倍体BMP-2的成骨活性,发现二倍体rhBMP-2的成骨活性明显高于单倍体rhBMP-2,并且随着BMP-2浓度增加,碱性磷酸酶活性上升。体内动物异位成骨实验发现rhBMP-2肌带植入小鼠体内3周后,取出的异位骨颗粒鲜艳饱满,骨结构完整;HE切片和Masson三色切片都显示出良好的异位成骨效果。此方法制备的rhBMP-2具有良好的诱导成骨分化能力,可用于骨组织修复,满足临床需要。     

大鼠骨髓间充质干细胞向成骨与成脂分化过程中相关基因的表达变化

目的探讨大鼠骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)向成骨与成脂分化过程中相关基因表达的变化。方法采用全贴壁法分离培养大鼠BMSCs,并观察其形态学特征的变化,MTT法检测其生长状况,并绘制生长曲线。分别采用成骨和成脂诱导剂对第4代BMSCs进行诱导分化,应用碱性磷酸酶试剂盒、茜素红和油红O染色液检测其ALP活性、成骨和成脂分化能力;RT-QPCR检测诱导0、7、14和21 d的成骨分化相关基因Runt相关转录因子2(Runx2)、骨钙素(osteocalcin,OCN)、碱性磷酸酶(ALP)及成脂分化相关基因过氧化物酶体增殖物激活受体γ(peroxidase proliferator activated receptor gamma,PPARγ)和脂肪酸结合蛋白(FABP4)的表达变化。结果全骨髓贴壁法能成功分离培养BMSCs,传代细胞生长增殖迅速,以长梭形细胞生长为主,细胞生长曲线呈S形。第4代BMSCs分别经成骨和成脂诱导剂诱导后,ALP、茜素红和油红O染色均呈阳性;诱导7、14和21 d后,Runx2、OCN、ALP、PPARγ和FABP4基因mRNA的表达量均显著高于0 d(P0.05);成骨分化过程中,Runx2和ALP在第7天时表达量最高,之后呈下降趋势,OCN的表达量呈稳定上升趋势;成脂分化过程中,PPARγ在第7天时表达量最高,FABP4始终高表达。结论 BMSCs具有易于体外分离培养、扩增和经诱导后具有多向分化潜能等特点,成骨和成脂分化相关基因的表达量随诱导时间延长而变化,呈明显的时序性表达差异,提示分别在成骨与成脂分化过程中起重要调控作用,为BMSCs在骨、细胞和基因等工程中的机制研究提供了实验依据。     

重组人骨形态发生蛋白-7工程菌的高密度发酵

目的建立重组人骨形态发生蛋白-7(rhBMP-7)工程菌的高密度发酵工艺。方法采用摇瓶及发酵罐培养工程菌BL21/pBV221-rhBMP-7,观察不同培养基、乙酸浓度、pH值、诱导时间等对工程菌菌体生长及目的蛋白表达的影响。在优化的发酵条件下培养工程菌,当菌体A600值达100时,42℃升温诱导,并对表达产物进行纯化。结果发酵培养基与LB培养基培养的工程菌目的蛋白的表达量无明显差异;乙酸可明显抑制菌体生长及目的蛋白表达;最适于菌体生长和目的蛋白表达的pH值分别为6.8和7.6;最佳诱导时间为3h。以优化的发酵条件培养的工程菌诱导3h后,目的蛋白的表达量可达菌体总蛋白的34.9%,最终菌体A600值可达139.5;经纯化的目的蛋白纯度可达95%以上。结论已初步建立了rhBMP-7工程菌的高密度发酵工艺。     

重组人骨形态发生蛋白-7复合体对牙槽骨再生的影响

目的观察基因重组人骨形态发生蛋白-7(rhBMP-7)与明胶海绵的复合体对犬牙槽骨再生的影响。方法犬拔牙创内植入rhBMP-7与明胶海绵的复合体,以自然愈合拔牙创为对照。于术后2、4、8周分别将犬处死,取拔牙创处牙槽骨标本,行X线和组织学切片检查,观察成骨情况及牙槽骨萎缩情况。结果X线及组织学切片显示实验侧成骨速度及成骨质量明显优于对照侧。结论rhBMP-7与明胶海绵复合体是一种可促进牙槽骨再生的新型生物复合材料。     

转化生长因子-β在骨髓间充质干细胞治疗实验性自身免疫性重症肌无力机制中的作用

目的探讨转化生长因子-β(TGF-β)在骨髓间充质干细胞(BMSCs)治疗实验性自身免疫性重症肌无力(EAMG)机制中的作用。方法分离培养健康Lewis大鼠BMSCs,并进行大量体外扩增;以大鼠来源的乙酰胆碱受体(R-AChR)2次免疫Lewis大鼠,建立EAMG模型;第2次免疫的同时,经尾静脉移植BMSCs,1×107个/只,依据Lennon评分标准,进行体重测量和临床体征评定。并通过体外实验进一步探讨TGF-β在治疗EAMG过程中的具体机制。结果BMSCs移植明显缓解了EAMG的临床症状,临床评分及体重变化差异均有统计学意义,表明治疗有效;体外实验结果显示,BMSCs能通过TGF-β的分泌影响AChR特异性Th17/Treg细胞亚群的分布及其相关因子的分泌,以anti-TGF-β抗体封闭后,这种调节作用在一定程度上被抑制。结论BMSCs通过细胞因子TGF-β,能在一定程度上调节AChR特异性Th17/Treg细胞亚群的平衡,从而起到治疗EAMG的作用。     

人骨形态发生蛋白-7在人骨肉瘤细胞U2-OS中的表达

目的探讨人骨肉瘤细胞U2-OS表达重组人骨形态发生蛋白-7(recombinant human bone morphogenetic protein-7,rhBMP-7)的可行性。方法将hBMP-7成熟肽基因片段克隆至载体pcDNA3.1上,构建真核表达质粒pcDNA3.1-rhBMP-7。利用Lipofectamine 2000将重组质粒转染至U2-OS细胞中,采用实时荧光定量PCR及Western blot法检测细胞中hBMP-7基因mRNA和rhBMP-7的表达。结果真核组表达质粒pcDNA3.1-rhBMP-7经NdeⅠ和EcoRⅤ双酶切及测序鉴定证明构建正确。pcDNA3.1-rhBMP-7质粒转染的U2-OS细胞中hBMP-7基因mRNA和rhBMP-7的表达水平均明显高于pcDNA3.1载体转染的细胞(P0.05)。结论成功构建了hBMP-7基因的重组表达质粒,并在U2-OS细胞中成功表达,为进一步研究hBMP-7的制备方法和建立新的表达系统奠定了基础。     

骨形态发生蛋白9-2双表达定向诱导多潜能干细胞C3H10的成骨分化

目的探讨骨形态发生蛋白(Bone morphogenetic protein,BMP)9-2双表达定向诱导多潜能干细胞C3H10向成骨细胞分化的情况。方法将C3H10细胞分为4组:BMP9-2、BMP2、BMP9和GFP组,将4种重组腺病毒分别感染C3H10细胞,通过碱性磷酸酶(Alkaline phosphatase,ALP)染色、定量测定及钙茜素红染色,观察BMP9-2双表达对C3H10细胞成骨分化的定向诱导作用。结果 BMP9-2双表达能诱导C3H10细胞ALP的表达,其染色活性高于BMP2组1.6倍,BMP9组2.5倍,GFP组4倍;其BMP9-2双表达定量表达A520值在病毒感染后5、7、9 d均高于BMP2、BMP9和GFP组;BMP9-2双表达能诱导C3H10细胞钙盐的沉积,感染14 d后,钙茜素红染色可见钙化结节,其染色活性高于BMP2组1.4倍,BMP9组1.3倍,GFP组5.2倍。结论 BMP9-2双表达能定向诱导C3H10细胞成骨分化,其成骨活性强于单一成骨诱导因子BMP2和BMP9。     

Polyvinyl alcohol associated with carbon nanotube scaffolds for osteogenic differentiation of rat bone mesenchymal stem cells

Polyvinyl alcohol (PVAl) hydrogel, alone and reinforced with two types of carbon nanoparticles, was studied in cultured cells to assess its potential use in treating osteochondral defects. The carbon nanoparticles were produced by hot-filament chemical vapour deposition. The carbon material was characterised with a Renishaw Invia Raman microscope system and the morphological particles were characterised with field emission scanning electron microscopy and high-resolution transmission electron microscopy. Cytotoxicity was evaluated by measuring the Vero fibroblast-type cells’ metabolic activity and studying their morphology. The osteogenic differentiation of mesenchymal stem cells obtained from rat bone marrow was evaluated by alkaline phosphatase (ALP) and alizarin red S (ARS) staining. Cell viability and morphology were assessed with thiazolyl blue tetrazolium bromide and scanning electron microscopy, respectively. The materials did not interfere with the viability, metabolic activity, morphology and spreading of either of the cell types analysed. Nodules of mineralised organic matrix were identified with ARS and ALP, confirming osteogenic differentiation. These results indicated higher concentration of ALP and mineralised matrix for PVAl with carbon nanoparticles. The results of this study indicate the potential use of carbon nanoparticles with PVAl hydrogels as orthopaedic biomaterials to treat osteochondral defects, but further in vivo investigations are still necessary.     

An oligodeoxynucleotide that induces differentiation of bone marrow mesenchymal stem cells to osteoblasts in vitro and reduces alveolar bone loss in rats with periodontitis

To investigate the effect of oligodeoxynucleotides (ODNs) on the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) to osteoblasts, in order to find a candidate ODN with potential for the treatment of periodontitis, a series of ODNs were designed and selected to test their effect on the promotion of the differentiation of BMSCs to osteoblasts in vitro and on the repair of periodontal tissue in rats with periodontitis. It was found that MT01, one of the ODNs with the sequences of human mitochondrial DNA, stimulated the proliferation of BMSCs, the differentiation of BMSCs to osteoblasts and mRNA expression of bone-associated factors including Runx2, Osterix, OPG, RANKL and collagen I in vitro. In vivo study showed that MT01 prevented the loss of alveolar bone in the rats with periodontitis and induced the production of proteins of OPG and Osterix in the bone tissue. These results indicated that MT01 could induce differentiation of BMSCs to osteoblasts and inhibit the alveolar bone absorption in rats with periodontitis.     

Minimal perfusion flow for osteogenic growth of mesenchymal stem cells on lattice scaffolds

A modeling approach to identify sets of culture conditions to promote homogeneous growth of cells in perfusion bioreactors equipped with regular shape scaffolds is proposed. We identify cases in which dynamic culturing is necessary using a zero‐dimensional mass transport and reaction model. Then, based on the three‐dimensional (3‐D) rendering of the flow field inside the bioreactor, we identify regions where cellular growth may become critical; finally, using a 1‐D mass transport and reaction model, we calculate the minimal perfusion flow necessary to maintain the cellular growth rate above a target threshold. The developed approach is used to analyze culturing conditions inside an indirect perfusion bioreactor equipped with a lattice scaffold. Regions where the perfusion flow is inadequate to foster cellular growth at the desired rate are identified. The perfusion flow required to maintain the target growth rate inside the bioreactor is calculated. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3131–3144, 2013     

Effects of high glucose on vascular endothelial growth factor synthesis and secretion in aortic vascular smooth muscle cells from obese and lean zucker rats

Type 1 diabetes is characterized by insulin deficiency, type 2 by both insulin deficiency and insulin resistance: in both conditions, hyperglycaemia is accompanied by an increased cardiovascular risk, due to increased atherosclerotic plaque formation/instabilization and impaired collateral vessel formation. An important factor in these phenomena is the Vascular Endothelial Growth Factor (VEGF), a molecule produced also by Vascular Smooth Muscle Cells (VSMC). We aimed at evaluating the role of high glucose on VEGF-A(164) synthesis and secretion in VSMC from lean insulin-sensitive and obese insulin-resistant Zucker rats (LZR and OZR). In cultured aortic VSMC from LZR and OZR incubated for 24 h with d-glucose (5.5, 15 and 25 mM) or with the osmotic controls l-glucose and mannitol, we measured VEGF-A(164) synthesis (western, blotting) and secretion (western blotting and ELISA). We observed that: (i) d-glucose dose-dependently increases VEGF-A(164) synthesis and secretion in VSMC from LZR and OZR (n = 6, ANOVA p = 0.002-0.0001); (ii) all the effects of 15 and 25 mM d-glucose are attenuated in VSMC from OZR vs. LZR (p = 0.0001); (iii) l-glucose and mannitol reproduce the VEGF-A(164) modulation induced by d-glucose in VSMC from both LZR and OZR. Thus, glucose increases via an osmotic mechanism VEGF synthesis and secretion in VSMC, an effect attenuated in the presence of insulin resistance.     

Evaluation of the chondrogenic differentiation of mesenchymal stem cells on hybrid biomimetic scaffolds

Hybrid materials are widely and promisingly used as scaffolds in cartilage tissue remodeling. In this study, hybrid scaffolds consist of polycaprolactone (PCL), poly(vinyl alcohol) (PVA) with/without gelatin (GEL) to mimic natural cartilage extracellular matrix (ECM) were investigated. Scaffolds were prepared by freeze drying and characterized by scanning electron microscopy and compressive mechanical testing. Biological assays of mesenchymal stem cell (MSC) cultures, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, and dimethyl methylene blue were performed, and real‐time polymerization chain reaction analysis of the cartilage‐specific ECM gene marker expression was done. The results show an open interconnected porous structure with a compression modulus of 1.27 ± 0.04 MPa. The surface of the scaffolds showed an excellent efficiency in the adhesion and proliferation of MSCs. A significant increase in the proteoglycan content from 3.70 ± 0.96 to 5.4 ± 1.13 μg/mL was observed after 14 days in the PCL–PVA–GEL scaffolds. The expression amount of the sex‐determining region Y–Box 9 (SOX9) and collagen II (COL2) mRNA levels of the MSCs showed significant increases in SOX9 and COL2, respectively in comparison with PCL–PVA scaffold. The study revealed that the aforementioned scaffold as a blend of natural and synthetic polymers may be a promising substrate in tissue engineering for cartilage repair with MSC transplantation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40635.     

血管内皮生长因子化学发光免疫测定试剂盒的研制及验证

目的研制血管内皮生长因子(vascular endothelial growth factor,VEGF)化学发光免疫测定试剂盒,并对该试剂盒进行验证。方法以试剂盒的技术指标和血清检测结果为参考依据,建立检测方法,确定检测范围,并对包被抗体(1∶500、1∶1 000和1∶2 000倍稀释)及酶标抗体浓度(1∶3 000、1∶5 000、1∶6 000和1∶8 000倍稀释)、包被温度(室温和4℃)、封闭液成分(1%小牛血清、1%和0.5%牛血清白蛋白)及干燥方法(超净台吹干和使用真空干燥机进行干燥)进行优化;同时对试剂盒的线性、检出限、精密性、准确度、特异性及热稳定性进行验证;采用本试剂盒对139例非肿瘤人群和100例肿瘤患者的血清样本进行初步检测。结果方法的最佳检测条件为:包被抗体浓度为1∶1 000,酶标抗体浓度为1∶3 000,对血清样本的检测范围为6.25~800 pg/ml,最佳包被浓度为4℃,最佳封闭液成分为0.5%牛血清白蛋白,最佳干燥方法为真空干燥法。试剂盒线性相关系数r0.99,校准曲线各点偏差的绝对值10%,最低检出限≤3.125 pg/ml,空白检出限≤3.125 pg/ml,批内差异5%,批间差异7%,回收率为85%~99%;特异性检验结果为本试剂盒对EGF、FGF-2、PDGF-AA、Pl GF-1、Pl GF-2、HGF、TNF-α、TNF-β检测的交叉反应率≤0.52%;经37℃保存3、7 d后,试剂盒线性相关系数r0.99,空白检出限≤3.125 pg/ml,批内差异8%,回收率为80%~82%。139例非肿瘤人群和100例肿瘤患者的血清样本中VEGF的中位水平(M)分别为44.6和83.4 pg/ml。结论本研究开发的试剂盒具有较高的准确性、灵敏性、特异性,适用于血清VEGF的临床检测,具有较好的临床应用前景。     

血管内皮生长因子受体3和神经纤毛蛋白2对胃癌SGC-7901细胞增殖和凋亡的影响

目的探讨分别阻断和联合阻断血管内皮生长因子受体3(Vascular endothelial growth factor receptor 3,VEGFR3)及神经纤毛蛋白2(Neuropilin 2,NRP2)基因的表达对人胃癌SGC-7901细胞株增殖和凋亡的影响。方法将SGC-7901细胞株分为3大组,VEGFR3阻断组、NRP2阻断组和VEGFR3+NRP2阻断组,各大组中又包含空白对照组、脂质体转染组、无义链转染组(NSODN组)和不同浓度反义链转染组(ASODN组)。转染后的各组SGC-7901细胞株经RT-PCR法检测VEGFR3-mRNA及NRP2-mRNA的转录水平。分别采用MTT法和流式细胞术检测细胞的增殖和凋亡情况。结果反义链转染组VEGFR3-mRNA和NRP2-mRNA的转录水平明显低于其各自的空白对照组、脂质体转染组和NSOND组,表明该组成功阻断基因VEGFR3和NRP2的表达。各组细胞的增殖和凋亡情况差异有统计学意义(P<0.05),并呈剂量和时间依赖性。在相同条件下,单独转染VEGFR3-ASODN组对胃癌细胞增殖的抑制及促凋亡作用优于单独转染NRP2-ASODN组,而联合转染组对细胞增殖的抑制及促凋亡作用最明显。结论阻断VEGFR3基因的表达对细胞增殖凋亡的影响大于阻断NRP2基因,联合阻断两个基因的表达,对细胞增殖和凋亡的影响明显大于单独阻断组。     

腺病毒介导的slit2 shRNA对缺氧诱导的人视网膜色素上皮细胞中血管内皮生长因子表达的影响

目的观察腺病毒介导的slit2 shRNA对缺氧诱导的人视网膜色素上皮细胞(retinal pigment epithelial cells,RPE)中血管内皮生长因子(vascular endothelial growth factor,VEGF)表达的影响,探讨slit2在脉络膜新生血管(chorodal neovascularation,CNV)中的可能作用,为CNV的治疗提供新的思路。方法分别采用RT-PCR和免疫组化法检测人视网膜色素上皮-19(ARPE-19)细胞中slit2及受体Robo1基因mRNA的转录和蛋白的表达;用200μmol/L氯化钴处理人ARPE-19细胞,建立化学缺氧模型,以未缺氧组作为对照,采用Real-time PCR和Western blot法检测在缺氧状态下细胞中slit2、Robo1、VEGF基因mRNA及蛋白水平表达的变化;将缺氧的人ARPE-19细胞随机分为shRNA处理组(加入Ad-slit2-shRNA)、空腺病毒组(加入空腺病毒)和缺氧组,24 h后收集各组细胞,Real-time PCR和Western blot法检测slit2 shRNA干扰后细胞中slit2、Robo1、VEGF基因mRNA和蛋白水平表达的变化,ELISA法检测细胞培养上清中VEGF蛋白水平的变化。结果在正常人ARPE-19细胞中有slit2和Robo1基因mRNA的转录及蛋白的表达;缺氧组人ARPE-19细胞中slit2、Robo1、VEGF基因mRNA和蛋白的表达水平均较未缺氧组明显升高(P0.05);与缺氧组相比,slit2-shRNA处理组人ARPE-19细胞中slit2、Robo1、VEGF基因mRNA和蛋白的表达水平均明显降低(P0.05),缺氧组与空腺病毒组slit2、Robo1、VEGF的变化差异无统计学意义(P0.05)。结论 slit2 shRNA沉默RPE细胞中的slit2后,可明显抑制缺氧诱导的RPE细胞中VEGF的表达,为临床CNV的治疗提供了新的思路。