VEGF165过表达对BMP2成骨细胞分化影响的实验研究

[目的]探讨腺病毒转染血管内皮生长因子165(vascular endothelial growth factor 165,VEGF165)对骨形态发生蛋白(bone morphogenetic protein 2,BMP2)促成骨细胞分化的抑制性作用研究。[方法]采用密度梯度离心法分离兔骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BMSCs),取第3代BMSCs进行细胞表型鉴定并作为细胞实验对象,使用Ad-BMP2和Ad-BMP2-VEGF165载体体外转染BMSCs,倒置荧光显微镜下观察GFP表达变化;同时ELISA和Western blot检测BMP2和VEGF165蛋白的表达。然后,应用成骨细胞诱导培养液定向诱导BMSCs向成骨细胞分化。实验分3组:Ad-BMP2-VEGF165转染BMSCs组(Ad-BMP2-VEGF165组),AdBMP2转染BMSCs组(Ad-BMP2组),BMSCs组(对照组)。分别在成骨细胞诱导培养后7、14、21 d,通过Real-time PCR分析ALP和OC mRNA相对表达水平和碱性磷酸酶(alkaline phosphatase,ALP)活性测定、骨钙素(Osteocalcin,OC)免疫组化染色来评价各组BMSCs成骨分化潜能的影响。[结果]第3代细胞表面高表达CD29(99.82%)、CD44(94.14%),低表达CD14(3.11%)、CD34(0.34%);腺病毒转染后第5 h BMP2和h VEGF165蛋白水平表达最高;成骨细胞诱导培养14和21 d后,Ad-BMP2组成骨相关基因表达、OC免疫组化和ALP活性表达最高,结果与其他两组相比较差异具有统计学意义(P<0.05);而对照组表达最弱,与Ad-BMP2-VEGF165组比较差异具有统计学意义(P<0.05)。[结论]腺病毒载体Ad-BMP2与Ad-BMP2-VEGF165转染BMSCs后,均具有明显促进BMSCs体外诱导成骨细胞分化潜能,但Ad-BMP2诱导作用更为显著,同时说明VEGF165可能对BMSCs成骨细胞分化起抑制作用。     

hBMP2/hVEGF165双基因腺病毒修饰BMSCs复合n-HA/PA66修复骨缺损影像学观察

[目的]探讨携带h BMP2/h VEGF165双基因重组腺病毒共修饰BMSCs复合多孔n-HA/PA66修复兔桡骨大段骨缺损在不同时相点影像学动态变化和临床影像评估的可靠性。[方法]选取40只成年新西兰大白兔,雄性,体重2.8~3.1 kg,采用完全随机法分为2大组,每组20只,手术制作15 mm双侧桡骨中段骨缺损模型。A1组:左侧骨缺损处不植入任何材料为空白对照组;A2组:右侧骨缺损处植入h BMP2/BMSCs/n-HA/PA 66人工骨材料;B1组:左侧骨缺损处植入BMSCs/n-HA/PA66人工骨材料;B2组:右侧骨缺损处植入h BMP2/h VEGF165/BMSCs/n-HA/PA 66人工骨材料。分别于术后2、4、8、12周进行X线、CT三维重建观察和甲苯胺蓝组织染色观察。[结果]B2组各个时期Lane-Sandhu法X线射线评分均高于其他各组,差异有统计学意义(P0.05),A2组优于B1组(P0.05),A1组最差(P0.05);且CT三维重建骨形成量和组织染色效果均优于同期其他各组。[结论]h BMP2/h VEGF165双基因重组腺病毒共修饰BMSCs复合多孔n-HA/PA66人工骨材料治疗兔大段骨缺损,影像学观察,直观、形象地显示了其持久、稳定、高效的骨修复作用,为基因治疗复合人工骨材料修复骨缺损提供了良好的实验依据。     

共表达腺病毒载体构建鉴定及其转染骨髓间充质干细胞观察

目的：构建并鉴定绿色荧光蛋白标记的人骨形态发生蛋白（bone morphogenetic protein,BMP）2和血管内皮生长因子（vascular endotheliel growth factor,VEGF）165双基因共表达的重组腺病毒,为研究该双基因对骨髓间充质干细胞成骨方向诱导和体内骨缺损修复作用奠定基础。方法：从cDNA文库中PCR扩增BMP2和VEGF165目的基因,并将其插入腺病毒穿梭质粒pAd-MCMV-GFP的多克隆位点,将构建的重组穿梭质粒pAd-MCMV-BMP2-VEGF165和腺病毒辅助质粒pBHGloxΔE1,3Cre共转染细胞HEK293细胞内,经历腺病毒基因重组及出毒后收集细胞,多次冻融离心获取病毒溶液（Ad-BMP2-VEGF165）。进一步纯化并测定病毒滴度,随后通过转染兔骨髓间充质干细胞并检测BMP2和VEGF165双目的基因表达和倒置荧光显微镜下观察绿色荧光蛋白表达。结果：基因测序、菌落PCR、Western blotting、Real-time PCR、绿色荧光蛋白表达均表明载体Ad-BMP2-VEGF165构建成功,可稳定转染骨髓间充质干细胞内并稳定表达,经测定腺病毒载体滴度达到1×10¹⁰ PFU/ml。结论：携带人BMP2和VEGF165双基因共表达重组腺病毒载体构建成功,并能获得高滴度的病毒感染液。     

重组腺病毒体外诱导山羊骨髓间充质干细胞成骨分化的研究

目的 探讨腺病毒介导骨形态发生蛋白2(BMP2)和碱性成纤维细胞生长因子(bFGF)双基因体外转染山羊骨髓间充质干细胞(BMSCs)后目的基因表达与诱导成骨情况. 方法 从2岁健康雌性山羊髂骨处骨穿抽取骨髓2ml,利用密度梯度离心法分离培养山羊BMSCs,将前期构建好的腺病毒载体Ad-BMP2-bFGF、Ad-BMP2分2组,以MOI=5000分别转染BMSCs,每2d用ELISA法检测BMP2和bFGF的表达情况,每周用ALP染色试剂盒及定量试剂盒检测ALP表达情况. 结果 Ad-BMP2-bFGF转染BMSCs 48 h后,目的蛋白已有显著表达(BMP2为3996.22 pg/ml、bFGF为1352.15 pg/ml),第6天达到高峰(BMP2为5146.63 pg/ml、bFGF为1434.75pg/ml),与未转染组比较差异有统计学意义(P＜0.05),3周后细胞呈现明显的成骨改变,ALP活性明显增高(266mol/L),Ad-BMP2-bFGF组ALP表达量约为Ad-BMP 2组的1.5倍(P＜0.05). 结论 经Ad-BMP2-bFGF转染的BMSCs具有持续高水平目的蛋白表达活性,转染后的BMSCs表现出明显的成骨活性,成骨活性明显强于Ad-BMP2组.     

血管内皮生长因子重组腺病毒转染鼠骨髓基质细胞及其产物促内皮细胞增殖的研究

目的探讨腺病毒介导血管内皮生长因子165(VEGF165)基因转染骨髓基质细胞(BMSCs)后对VEGF基因的转录、表达及其产物生物活性的影响。方法体外培养4只大鼠骨髓基质细胞,用携带VEGF165基因的重组腺病毒转染培养细胞;通过逆转录聚合酶链反应、免疫印记法和酶联免疫吸附法检测VEGF在转染细胞内的转录、表达和细胞外分泌情况;通过血管内皮细胞增殖实验测定转染VEGF165基因后的BMSCs培养上清中VEGF蛋白的生物活性。结果腺病毒介导VEGF165基因转染BMSCs后可以获得有效的转录及表达,其分泌于培养上清中的表达产物可明显促进大鼠主动脉血管内皮细胞的增殖(P<001),具有很强的生物学活性。结论腺病毒可安全、有效地转染BMSCs,VEGF165基因转染的鼠BMSCs可有效表达具有生物活性的VEGF蛋白。     

腺病毒介导入VEGF165和ANG-1双基因转染大鼠BMSCs及对其增殖的影响

[目的]探讨携带人血管内皮细胞生长因子165(VEGF165)和血管生成素-1(ANG-1)双基因的腺病毒表达载体pAd-VIA转染大鼠骨髓基质干细胞(BMSCs)的体外表达及对BMSCs增殖的影响.[方法]将本室构建的编码人VEGF165和ANG-1双基因的腺病毒质粒pAd-VIA在QBI-293A细胞内进行包装和扩增,体外转染大鼠BMSCs,通过绿色荧光蛋白(GFP)表达、Western-blotting、酶联免疫吸附分析(ELISA)方法检测外源基因的表达,利用MTT法检测MOI(multiplicity of infection)=50、100、200、400 pfu/cell不同浓度腺病毒转染后对BMSCs增殖活性的影响.[结果]重组腺病毒质粒pAd-VIA在QBI-293A细胞内成功包装和扩增,体外转染BMSCs后,有大量的GFP 表达,Western-blotting检测显示,转染组与VEGF165和ANG-1抗体结合,在45 KD和14.4 KD左右出现印迹条带;ELISA结果显示:转染组第1、2、3 d,上清中的VEGF165浓度和ANG-1浓度持续增加,未转染组均未检测到外源基因的表达,差异有统计学意义(P<0.01);不同浓度的腺病毒载体转染BMSCs后,促进细胞增殖,细胞生长曲线上移,在1、3、5、7 d转染组的OD值均大于未转染组,差异有统计学意义(P<0.01),第9 d,细胞进入平台期,转染组和未转染组的OD值差异无统计学意义(P>0.05).[结论]重组腺病毒pAd-VIA转染大鼠BMSCs后,外源基因在体外得到有效表达,同时在观察时间内可以促进大鼠BMSCs的增殖.     

腺病毒介导人VEGF_(165)和ANG-1双基因转染大鼠BMSCs及对其增殖的影响

[目的]探讨携带人血管内皮细胞生长因子165(VEGF165)和血管生成素-1(ANG-1)双基因的腺病毒表达载体pAd-VIA转染大鼠骨髓基质干细胞(BMSCs)的体外表达及对BMSCs增殖的影响。[方法]将本室构建的编码人VEGF165和ANG-1双基因的腺病毒质粒pAd-VIA在QBI-293A细胞内进行包装和扩增,体外转染大鼠BMSCs,通过绿色荧光蛋白(GFP)表达、Western-blotting、酶联免疫吸附分析(ELISA)方法检测外源基因的表达,利用MTT法检测MOI(multiplicity of infection)=50、100、200、400 pfu/cell不同浓度腺病毒转染后对BMSCs增殖活性的影响。[结果]重组腺病毒质粒pAd-VIA在QBI-293A细胞内成功包装和扩增,体外转染BMSCs后,有大量的GFP表达,Western-blotting检测显示,转染组与VEGF165和ANG-1抗体结合,在45 KD和14.4 KD左右出现印迹条带;ELISA结果显示:转染组第1、2、3 d,上清中的VEGF165浓度和ANG-1浓度持续增加,未转染组均未检测到外源基因的表达,差异...     

BMP-2基因转染的人骨髓基质干细胞复合PLA/PCL支架体外构建组织工程骨

目的　用人骨形态发生蛋白 2腺病毒表达载体 (Ad -BMP - 2 )转染的人骨髓基质干细胞 (hBMSC) ,复合PLA/PCL(聚乳酸 /聚己内酯 )生物降解支架体外构建组织工程骨。方法　用Ad -BMP - 2转染体外培养的成人BMSC ,免疫组化、原位杂交染色和蛋白印迹方法检测细胞BMP - 2的表达 ,并通过流式细胞仪和ALP活性检测分析其对细胞增殖、分化的影响。然后将转染后细胞接种到PLA/PCL支架上 ,扫描电镜观察细胞贴附、生长状况。结果　转染后 ,hBMP - 2基因在mRNA水平和蛋白水平均有表达 ;S期细胞比例和ALP活性明显增高。扫描电镜见转染细胞分布均匀 ,伸展良好。结论　Ad-BMP - 2可高效转染hBMSC ,且促进细胞增殖及成骨转化。转染后细胞在PLA/PCL上生长良好 ,BMP - 2基因治疗的组织工程骨构建成功     

Ad-BMP-2/GFP转染兔骨髓间充质干细胞前后生物学特性的研究

目的：对Ad－BMP－2／GFP转染兔骨髓间充质干细胞（ BMSCs ）前后的生物学特性进行观察。方法采用密度梯度离心结合贴壁培养法分离获取第10代兔BMSCs,应用流式细胞仪检测细胞表面抗原CD44、CD45、CD29的表达,用携带BMP2和GFP基因的腺病毒转染细胞。分别通过倒置荧光显微镜下观察转染前后细胞形态改变,MTT 法分析转染前后细胞增殖的情况,体外Ⅰ型胶原免疫组化染色和钙结节茜素红染色以观察转染前后细胞的成骨分化情况,Western Blot 检测转染前后细胞内目的蛋白表达。结果密度梯度离心结合贴壁培养法能获取高纯度第10代兔BMSCs ,流式细胞仪检测显示CD44、CD29阳性,CD45阴性。 Ad－BMP－2／GFP转染兔BMSCs后在荧光显微镜下观察到绿色荧光,细胞形态向成骨方向分化,在短时间内能促进兔BMSCs 的增殖（P＜0．05）,Ⅰ型胶原免疫组化染色、茜素红染色均呈阳性,Western Blot显示细胞内稳定表达BMP－2目的蛋白。结论 Ad－BMP－2／GFP能成功转染兔骨髓间充质干细胞并能改变其生物学特性。     

PcDNA3.1-VEGF165质粒转染神经母细胞瘤细胞后VEGF165的表达

目的观察PcDNA3.1-VEGF165质粒转染神经母细胞瘤细胞(SH-SY5Y)后VEGF165在体外的表达.方法将PcDNA3.1-VEGF165质粒应用脂质体介导的方法转染到SH-SY5Y(I组),同时建立空白对照组(Ⅱ组),两组其他试验条件均保持一致.脂转48h后,用ELISA和Westem-blot定量检测VEGF165可溶性产物.应用RT-PCR对SH-SY5Y产生的mRNA进行定性检测.对两组EUSA的定量结果进行统计学分析比较.结果脂转组(I组)PcDNA3.1-VEGF165质粒转染48h后神经母细胞瘤细胞即有VEGF165高效表达,RT-PCR可扩增到一条特异性的泳带,Western-blot显示转基因神经母细胞瘤细胞上清液中有一分子量为23kD的特异性条带.空白对照组(Ⅱ组)有微量的 VEGF165表达(84.14±33.89ng/ml),脂转组的VEGF165表达量(1005.15±185.50ng/ml)明显高于对照组.两组比较差异有显著性(P＜0.05).结论神经母细胞瘤细胞体外培养有微量VEGF165表达,PcDNA3.1-VEGF165质粒可通过脂质体转染体外培养的神经母细胞瘤细胞,被转染的神经母细胞瘤细胞能够高效表达VEGF165.     

跖骨感染骨外露的显微外科治疗

[目的]回顾总结跖骨骨感染骨外露的显微外科治疗方法。[方法]自1995年～2005年采用显微外科技术治疗214例跖骨骨外露骨感染患者。[结果]全部病例获得随访1～10年，平均随访3年，14例游离植皮术后皮肤成活良好，199例术后皮瓣全部成活，1例腓肠神经营养血管皮瓣移位修复术出现远端部分皮肤坏死，后经换药处理后，伤口自然愈合。皮瓣移植术后质地良好，无溃疡复发。患足均可负重走路。[结论]应用显微外科技术治疗跖骨骨感染骨外露可获得较好的疗效。     

Assessment of bone density and bone loss

Osteoporosis International - Dual-energy X-ray absorptiometry has become the standard for the evaluation of osteoporosis. It is useful both for identifying those people who are going to be at risk...     

Spinal fusions: bone and bone substitutes

Vertebral arthrodesis is one of the most commonly performed, yet incompletely understood, procedures in spinal surgery. Despite major progress in internal fixation techniques, the high rate of non-unions indicates that physiologic, biologic and molecular events that are crucial to this process are not well known. This article will analyze the general biology of bone regeneration, and particularly discuss the properties and use of various bone graft materials and graft substitutes. Received: 9 August 2000/Accepted: 11 August 2000     

Trabecular bone remodeling and bone balance in hyperthyroidism

In vivo tetracycline double-labeled iliac crest bone biopsies from 15 hyperthyroid patients were used for the reconstruction of curves describing the variation of resorption depth and formation thickness with time. The curves emerging were compared to curves reconstructed from 13 age- and sex-matched normal individuals (mean age 44 years). The median function period for resorptive cells in hyperthyroid patients (16 days) was about one-third the resorptive period in normals (51 days). No significant difference between the osteoclast-, mononuclear-, or preosteoblast-like cell resorption depths could be demonstrated between the two groups. Consequently, the median resorption rate in hyperthyroid patients (3.8 μm/day) was more than 3 times higher than the value in the control group (1.1 μm/day). Median Sigma_f, was shorter in the hyperthyroid group (109 days) than in the control group (151 days, P < 0.05), as was the median initial mineralization lag time (5 and 16 days, respectively, P < 0.01). No significant difference between the measured mean completed wall thickness (mcwT) values in the hyperthyroid groups and the control group could be demonstrated (58.1 and 60.5 μm respectively). Median initial mineralization rate in the hyperthyroid group (1.2 μm³/μm² per day) was not significantly higher than the value calculated in the control group (0.9 μm³/ μm² per day), but median initial matrix appositional rate in hyperthyroids (4.8 μm³/μm² per day) was 3 times higher than the value calculated for normals (1.6 μm³/μm² per day) (P < 0.01). Direct measurements of mean completed wall thickness in the hyperthyroid group gave results (58.1 μm) that were not in accordance with the mean completed wall thickness calculated from the growth curve (52.1 μm, P < 0.02). In normals no such discrepancy could be demonstrated. Using the mcwT value estimated from the growth curve, the bone formation period was calculated to 90 days for hyperthyroid patients. This maximal estimate for mcwT was also significantly lower than the mean resorption depth measured in the hyperthyroid group (61.7 μm, P < 0.05), which means that a net negative balance per remodeling cycle existed in the hyperthyroid group. Bone balance was preserved in the control group.     

骨胶原与骨质疏松骨密度及骨生物力学的相关性研究

目的探讨骨胶原含量在绝经后骨质疏松症的发生、发展及在骨质疏松性骨折中的作用。方法取7个月龄未交配雌性SD大鼠60只，随机分为四组，A组：对照组（sham组）；B组：切除卵巢组；C组：切除卵巢＋雌激素治疗组；D组：切除卵巢＋降钙素治疗组。除A组外，其他三组通过切除双侧卵巢法12周后制成骨质疏松模型，24周后分别行k的力学特性、右侧股骨三点弯曲试验、羟脯氨酸含量、k骨密度（BMD）测定，Masson三色染色法显示骨胶原形态。结果A、C、D组与B组在k羟脯氨酸含量、BMD、k压缩力学参数值、右侧股骨生物力学参数值、骨胶原染色含量及形态方面差异均有统计学意义（P〈0．05），而A、C、D组之间差异无统计学意义（P〉0．05）。统计学分析显示羟脯氨酸含量与BMD及骨生物力学参数值呈直线相关性。结论骨质疏松的发生与骨胶原含量下降有关。骨胶原含量的下降与BMD降低及骨生物力学改变呈相关性。应用雌激素和降钙素治疗去势后骨质疏松大鼠，不仅可以提高其BMD含量和骨生物力学性能，而且还可以提高骨胶原的含量。     

Repair of long bone defects with demineralized bone matrix and autogenous bone composite

Background:

Repair of diaphyseal bone defects is a challenging problem for orthopedic surgeons. In large bone defects the quantity of harvested autogenous bone may not be sufficient to fill the gap and then the use of synthetic or allogenic grafts along with autogenous bone becomes mandatory to achieve compact filling. Finding the optimal graft mixture for treatment of large diaphyseal defects is an important goal in contemporary orthopedics and this was the main focus of this study. The aim of this study is to investigate the efficacy of demineralized bone matrix (DBM) and autogenous cancellous bone (ACB) graft composite in a rabbit bilateral ulna segmental defect model.

Materials and Methods:

Twenty-seven adult female rabbits were divided into five groups. A two-centimeter piece of long bone on the midshaft of the ulna was osteotomized and removed from the rabbits’ forearms. In group 1 (n=7) the defects were treated with ACB, in group 2 (n=7) with DBM, and in group 3 (n=7) with ACB and DBM in the ratio of 1:1. Groups 4 and 5, with three rabbits in each group, were the negative and positive controls, respectively. Twelve weeks after implantation the rabbits were sacrificed and union was evaluated with radiograph (Faxitron), dual-energy x-ray absorptiometry (DEXA), and histological methods (decalcified sectioning).

Results:

Union rates and the volume of new bone in the different groups were as follows: group 1 - 92.8% union and 78.6% new bone; group 2 - 72.2% union and 63.6% new bone; and group 3 - 100% union and 100% new bone. DEXA results (bone mineral density [BMD]) were as follows: group 1 - 0.164 g/cm², group 2 - 0.138 g/cm², and group 3 - 0.194 g/cm².

Conclusions:

DBM serves as a graft extender or enhancer for autogenous graft and decreases the need of autogenous bone graft in the treatment of bone defects. In this study, the DBM and ACB composite facilitated the healing process. The union rate was better with the combination than with the use of any one of these grafts alone.