携带肾上腺髓质素基因腺病毒体外转染骨髓间充质干细胞及其蛋白的表达

背景：肾上腺髓质素具有促进骨髓间充质干细胞增殖、生长及减少凋亡等作用。目的：观察携带肾上腺髓质素基因的腺病毒体外转染骨髓间充质干细胞及其蛋白的表达。方法：培养293A细胞,并扩增携带肾上腺髓质素基因的腺病毒（Ad-ADM）,实验分为对照组、空载体组和Ad-ADM转染组,3组分别于细胞长满至50%～60%时加入等量的无血清L-DMEM、Ad-lacZ和Ad-ADM,噬斑法检测扩增后腺病毒的滴度;贴壁法体外分离、扩增培养大鼠骨髓间充质干细胞;Ad-GFP体外感染骨髓间充质干细胞后检测转染效率;RT-PCR检测Ad-ADM转染后肾上腺髓质素mRNA的表达。结果与结论：病毒扩增后噬斑试验测定Ad-ADM的病毒滴度为1.1×109pfu/mL。Ad-ADM感染骨髓间充质干细胞后,肾上腺髓质素mRNA的表达明显增加,对照组、空载体组未见ADMmRNA表达;量化结果表明其表达量从第1天开始逐渐增加,第7天达高峰,在11d时仍可检测其表达。提示腺病毒对骨髓间充质干细胞有较高的转染效率。感染Ad-ADM后,骨髓间充质干细胞可有效表达肾上腺髓质素。     

肾上腺髓质素基因转染改善缺氧培养骨髓间充质干细胞的抗凋亡能力

背景:基因转染可以提高骨髓间充质干细胞在移植区的存活,但目前对肾上腺髓质素基因转染骨髓间充质干细胞在缺氧条件下增殖、凋亡及分泌情况的研究很少.目的:观察肾上腺髓质素基因转染对骨髓间充质干细胞在缺氧及无血清培养条件下增殖、凋亡、分泌血管内皮生长因子的影响.方法:贴壁法体外分离、扩增培养大鼠骨髓间充质干细胞.用x-gal染色测含肾上腺髓质素基因的重组腺病毒Ad-ADM对骨髓间充质干细胞的感染率.骨髓间充质干细胞分为未转染组、空载体组、Ad-ADM转染组.在缺氧、无血清条件下进行骨髓间充质干细胞的培养,在缺氧0,3,6,9,12,16,20,24 h CCK-8法检测细胞增殖情况,ELISA法检测检测细胞上清液肾上腺髓质素及血管内皮生长因子表达,TUNEL法检测细胞凋亡情况.结果与结论:重组腺病毒对骨髓间充质干细胞的转染率与病毒感染复数具有量效关系,病毒感染复数为150时细胞的感染率达95.4%.缺氧、无血清培养条件下,3组骨髓间充质干细胞均出现生长抑制、凋亡增加,但是肾上腺髓质素基因转染组于0,3,6,9,12,16 h细胞凋亡率显著低于其他两组(P﹤0.05).缺氧 9,12 h,骨髓间充质干细胞分泌肾上腺髓质素及血管内皮生长因子达到高峰,且Ad-ADM转染组显著增高于其他两组(P﹤0.05).提示在缺氧、无血清培养条件下 (<20 h),肾上腺髓质素基因转染可增强骨髓间充质干细胞抗凋亡能力,这可能与肾上腺髓质素、血管内皮生长因子表达增加有关.     

人LMP-1基因腺病毒重组体构建及其在骨髓间充质干细胞的表达

背景:LIM矿化蛋白1 (LIM Mineralization protein, LMP-1)是一种细胞内非分泌蛋白,主要在骨的钙化阶段起作用.目前发现LMP-1可以促进骨形态发生蛋白2和转化生长因子β1等多种蛋白质合成增加,提示其可能通过招募众多的成骨因子共同参与成骨细胞的分化.目的:应用AdEasy腺病毒载体系统构建人LMP-1基因的腺病毒重组体,并检测感染病毒的兔骨髓间充质干细胞LMP-1的表达.设计、时间及地点:开放性实验,于2006-03/2007-02在解放军第三军医大学西南医院中心实验室完成.材料:纯种新西兰大白兔3只,用于分离制备骨髓间充质干细胞.携带人LMP-1基因的plRES2-EGFP-LMP-1质粒由重庆医科大学附二院骨科保存;AdEasy腺病毒由美国Tong-Chuan He博士惠赠:人胚肾293细胞由重庆医科大学检验系王宏兵硕士惠赠.方法:以plRES2-EGFP-LMP-1质粒为模板进行PCR扩增,在下游引物中加入特定序列,使扩增出的LMP-1基因带有编码6个组氨酸(即His标签)的碱基序列,将其作为目的基因,TA克隆后测序.双酶切后插入至腺病毒穿梭质粒pAdtrack-CMV内,经Pme I线性化,在BJ5183菌内与骨架质粒pAdeasy-1的同源重组,构建重组腺病毒质粒pAd-LMP-1.通过脂质体介导在HEK293细胞内包装出复制缺陷的重组腺病毒Ad-LMP-1,扩增纯化后测定滴度,以最佳MOI值体外感染兔骨髓间充质干细胞,行RT-PCR及Western Blot法检测LMP-l表达.主要观察指标:重组腺病毒质粒pAd-LMP-l的鉴定,检测其滴度及感染效率.RT-PCR、Western Blot法检测感染细胞LMP-1mRNA及蛋白的表达.结果:[1]测序鉴定携带His标签的LMP-1基因的重组质粒pMDl8-T-LMP-1构建成功.包装扩增后获得滴度约3.5×109efu/mL的腺病毒重组体Ad-LMP-1.以150的MOI值感染兔骨髓间充质干细胞可以获得最佳感染效率,感染3d后达50%~70%. [2]病毒感染后的骨髓间充质干细表达LMP-1mRNA及蛋白.结论:成功构建携带His标签的人LMP-1基因的腺病毒重组体,证实感染重组病毒的骨髓间充质干细胞可有效表达LMP-1.     

表达hVEGF121/EGFP融合蛋白骨髓间充质干细胞的制备及缺氧干预

目的:构建携带增强型绿色荧光蛋白报告基因的人血管内皮细胞生长因子121的真核质粒,检测所制备的表达hVEGF121/EGFP融合蛋白的骨髓间充质干细胞在不同时长缺氧后血管内皮细胞生长因子的水平.方法:设计携带酶切位点的扩增引物,通过PCR技术扩增人血管内皮细胞生长因子121编码基因全序列,以粘端连接克隆法将其编码片段定向连接入质粒载体pEGFP-N2的多克隆位点中,构建pEGFP-N2-hVEGF121重组质粒,采用酶切法、PCR以及DNA序列测定法鉴定所构建的重组质粒.全骨髓差速贴擘法分离培养骨髓间充质干细胞,体外扩增传代.通过形态学观察及表面标记物进行细胞鉴定.通过阳离子脂质体介导pEGFP-N2-hVEGF121重组质粒转染体外培养的骨髓间充质干细胞,使用荧光显微镜检测hVEGF121/EGFP融合蛋白的表达.将制备好的表达hVEGF121/EGFP融合蛋白的骨髓间充质干细胞存体外缺氧环境下分别培养6,12,24h,另设相同缺氧干预下的空白骨髓间充质干细胞组,以转染空载pEGFP-N2质粒的骨髓间充质干细胞组作为对照,采用RT-PCR法检测血管内皮生长因子mRNA的表达量.结果:酶切鉴定法、PCR鉴定法、DNA序列测定皆证实pEGFP-N2-hVEGF121重组质粒构建成功.使用pEGFP-N2-hVEGF121重组质粒转染骨髓间充质干细胞后,荧光显微镜检测提示hVEGF121/EGFP蛋白在骨髓间充质干细胞中存在表达.在体外模拟心肌缺氧的环境下分别培养6,12,24h后,RT-PCR检测示转染重组质粒的骨髓间充质干细胞组各时间段缺氧后的血管内皮牛长因子mRNA表达量均高于对照组(P<0.01),且不同时间段间差异无显著性意义(P0.05);空白骨髓间充质干细胞的血管内皮生长因子mRNA表达量随缺氧时程的延长而增加.结论:[1]成功构建携带人VEGF121/EGFP融合蛋白表达基因的真核表达质粒,并在骨髓间充质干细胞中获得表达.[2]证实表达hVEGF121/EGFP融合蛋白的骨髓间充质干细胞能在24h以内的不同时长缺氧下,维持较空白骨髓间充质干细胞更强、更稳定的血管内皮生长因子表达.     

重组腺相关病毒介导增强型绿色荧光蛋白在骨髓间充质干细胞中的表达

目的:重组腺相关病毒是携带治疗目的基因的有效载体.骨髓间充质干细胞则可作为外源基因的载体和表达场所实验选择携带绿包荧光蛋白的腺相关病毒体外转染骨髓间充质干细胞,观察转染效果。方法:实验于2006-01/12在咸宁学院心血管疾病研究所和武汉大学心内科实验室完成清洁级成年SD大鼠6只.由武汉大学医学院试验动物中心提供,实验过程中对动物的处置符合动物伦理学标准。携带增强型绿色荧光蛋白的重组腺相关病毒载体由北京本元正阳基因技术公司提供,基因启动子为CMV,有效滴度4×10~(11)v.g/mL。全骨髓法分离大鼠骨髓间充质干细胞,于体积分数为0.1的胎牛血清中培养.扩增纯化至第3代。按感染复数分别为10~2.10~3.10~4,10~5 v.g/cell加入携带增强型绿色荧光蛋白的重组腺相关病毒。于4,8,24、48 h倒置相差荧光显微镜下观察腺相关病毒感染骨髓间充质干细胞的状态,随机记录200个细胞中增强型绿色荧光蛋白阳性表达率.计算感染效率。结果:①骨髓间充质干细胞转染效率:感染复数为10~3.10~4,10~5 v.g/cell时.转染8 h后骨髓间充质干细胞内可见绿色荧光蛋白的表达.其中105 v.g/cell感染效果最佳.于转染48 h时荧光强度达最高值.感染效率约28%②骨髓间充质干细胞经G418筛选后检测增强型绿色荧光蛋白阳性细胞率达98%。结论:介导绿色荧光蛋白的腺相关病毒转染骨髓间充质干细胞简便易行,感染复数为10~5v.g/cell时效果较佳,目的基因表达稳定,用于后续基因治疗具备一定的可行性。     

碱性成纤维细胞生长因子基因转染大鼠骨髓间充质干细胞后目的基因的表达

目的:观察碱性成纤维细胞生长因子基因转染大鼠骨髓间充质干细胞后bFGF目的基因的表达情况,并进行影响骨髓间充质干细胞的生物学特性分析。方法:实验于2005-03/2006-02在中山大学第二附属医院医学研究中心完成。①选择近交系4周龄雄性SD大鼠10只,贴壁法分离培养骨髓间充质干细胞,构建含bFGF基因的腺病毒表达载体,利用腺病毒介导转染SD大鼠骨髓间充质干细胞。②传2代后,将细胞接种12孔培养板,培养至90%融合时弃上清,调整转染病毒滴度范围为50～400。荧光显微镜下通过观察绿色荧光强度检测转染效果,以流式细胞仪检测细胞转染效率。③传2代后,胰酶消化,置于6孔板内,每孔细胞数量5×105,2d后细胞贴壁生长于盖玻片上,分别转染Ad.bFGF、Ad.GFP,同时设立空白对照。转染病毒滴度选择200。应用免疫组化和Western-Blot法鉴定碱性成纤维细胞生长因子的表达,ELISA法检测培养上清液中碱性成纤维细胞生长因子的浓度。观察转染后骨髓间充质干细胞形态和生长情况的变化。结果:①pcDNA3/bFGF的鉴定结果:成功构建碱性成纤维细胞生长因子腺病毒表达载体。②Ad.GFP转染骨髓间充质干细胞的效率测定:转染48h后,绿色荧光蛋白的表达明显增强。当转染病毒滴度≤200时,腺病毒的转染效率与病毒剂量呈明显的正相关(P<0.05),当>200时转染效率趋于稳定,均在96%以上。③Ad.bFGF转染骨髓间充质干细胞的表达情况:bFGF蛋白表达免疫组化检测可见转染Ad.bFGF骨髓间充质干细胞的胞浆内充满棕褐色颗粒,阳性表达率为86%,而转染Ad.GFP及空白对照的骨髓间充质干细胞均为阴性。Western-Blot示转染Ad.bFGF的细胞裂解产物中碱性成纤维细胞生长因子含量明显高于转染Ad.GFP及空白对照。ELISA检测结果表明转染Ad.bFGF的细胞培养上清液中碱性成纤维细胞生长因子浓度第15天达高峰1467ng/L,此后逐渐下降,但至转染第28天时仍显著高于空白对照(441ng/L,128ng/L,t=4.31,P<0.01)。④转染Ad.bFGF对骨髓间充质干细胞增殖的影响:骨髓间充质干细胞的增殖分化没有明显变化。结论:采用腺病毒介导的基因转染技术可以将碱性成纤维细胞生长因子转染至骨髓间充质干细胞中,并有外源性基因和蛋白的表达。提示骨髓间充质干细胞是碱性成纤维细胞生长因子基因治疗的理想载体。     

白细胞介素12重组腺病毒质粒转染骨髓间充质干细胞

背景:有研究表明,骨髓间充质干细胞易于外源基因的导入和表达,且具有较弱的免疫抗原性和免疫调节功能,强大的迁移力和趋瘤性,因而逐渐显露其具有作为抗肿瘤基因治疗负载体系的优越性.目的:拟应用白细胞介素12重组腺病毒质粒AdEasy-R细胞介素12转染骨髓间充质干细胞,构建表达外源性白细胞介素12的骨髓间充质干细胞.设计、时间及地点:以细胞为对象的开放性实验,于2008-06在辽宁医学院实验中心及中国医科大学实验中心完成.材料:原代骨髓间充质干细胞由辽宁医学院外科学实验室构建,白细胞介素12重组腺病毒载体AdlL-12由辽宁医学院分子生物学实验室构建.方法:分离培养SD大鼠骨髓间允质干细胞,免疫组织化学及流式细胞技术鉴定细胞表面标志物,应用腺病毒介导白细胞介素12基因转染大鼠骨髓间充质干细胞.主要观察指标:以反转录聚合酶链反应及Western Blotting技术检测转染后的骨髓间充质干细胞的白细胞介素12基因mRNA及蛋白表达. 结果:腺病毒介导白细胞介素12基因转染骨髓间充质干细胞后,通过反转录-聚合酶链反应及Westem Blotting技术检测,结果证实白细胞介素12基因在mRNA及蛋白水平均有表达,而未经转染的骨髓间充质干细胞内无白细胞介素12基因及蛋白表达.结论:应用白细胞介素12重组腺病毒质粒成功构建了在mRNA及蛋白水平表达外源性白细胞介素12基因的骨髓间充质干细胞.     

Ad5-增强型绿色荧光蛋白和rAAV2-增强型绿色荧光蛋白转染脂肪间充质干细胞的对比

背景:利用基因转染技术诱导脂肪间充质干细胞成软骨细胞已有报道,但腺病毒和腺相关病毒转染脂肪间充质干细胞各有不同,且腺相关病毒载体能否转染脂肪间充质干细胞众说不一.目的:观察Ad5-增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)和Raav2-EGFP转染脂肪间充质干细胞后增强型绿色荧光蛋白的表达及转染后细胞增值能力的变化.方法:脂肪组织来源于6月龄新西兰大白兔颈背部.机械消化和酶消化法分取脂肪间充质干细胞,体外培养扩增.分别采用腺病毒载体(Ad5-EGFP)和腺相关病毒载体(Raav2-EGFP)转染脂肪间充质干细胞,并观察EGFP的表达.Raav2-EGFP转染后,需加入2 Μl丁酸钠(1 mol/L).采用MTT法检测基因转染对脂肪间充质干细胞增殖能力的影响.结果与结论:体外培养的脂肪间充质干细胞呈扁平状和长梭形,细胞形态均一,传代稳定.Ad5-EGFP组和Raav2-EGFP组均能观察到较多荧光细胞,转染效率分别达到88%和83%.腺病毒和腺相关病毒载体均能转染脂肪间充质干细胞,且转染效率很高.腺相关病毒需要借助丁酸钠来提高其基因表达水平.     

重组腺病毒介导的肝细胞生长因子基因体外转染骨髓间充质干细胞源性脂肪细胞

背景:肝细胞生长因子可促进血管内皮细胞增生及新生血管形成,已广泛应用于病理性瘢痕、心肌缺血等的实验性治疗.目的:鉴于重组腺病毒的宿主范围广,探讨重组腺病毒介导的入肝细胞生长因子对骨髓间充质干细胞源性脂肪细胞转染效率、日的蛋白表达及细胞活性的影响.设计、时间及地点:2006-08/2007-07在解放军兰州军区兰州总医院完成的细胞对比实验.材料:清洁级2月龄Wistar大鼠25只用于制备骨髓间充质干细胞.携带绿色荧光蛋白基因的重组腺病毒毒株、重组腺病毒介导的人肝细胞生长因子由解放军兰州军区兰州总医院博士后科研工作站哈小琴博士惠赠.方法:向体外培养至第3代的骨髓间充质干细胞中加入含地塞米松、IBMX、牛胰岛素、吲哚美辛、胎牛血清的L-DMEM进行成脂诱导.以不同感染强度的携带绿色荧光蛋白基因重组腺病毒转染诱导后的脂肪细胞.重组腺病毒介导人肝细胞生长因子以最佳感染强度转染诱导后的脂肪细胞.主要观察指标:油红O染色检测成脂情况.流式细胞仪计数绿色荧光蛋白阳性表达,计算转染效率.EUSA法检测转染上清中肝细胞生长因子的表达,MTT法检测转染脂肪细胞的活性.结果:①骨髓间充质干细胞成脂诱导后胞质内富含橙红色的脂滴,成脂率(97.31±0.46)%.②以100 pfu/cell携带绿色荧光蛋白基因的重组腺病毒转染脂肪细胞72 h后,绿色荧光蛋白表达量达高峰,此时转染效率为65.39%.③以100 pfu/cell作为最佳感染强度转染脂肪绌胞72 h后,肝细胞生长因子的表达量为峰值.与未转染空白对照比较,转染后24,48,72,96,168 h脂肪细胞活性均无明显变化(t=0.024～0.092,P>0.05).结论:重组腺病毒可介导肝细胞生长因子基因转染骨髓间充质干细胞来源的脂肪细胞,有效表达目的蛋白,且转染该基因对脂肪细胞的活性无影响.     

重组腺病毒介导增强型绿色荧光蛋白基因转染兔骨髓间充质干细胞

背景:目前仍没有合适的标记方法追踪观察兔骨髓间充质干细胞组织修复及基因治疗的效果.目的:观察重组腺病毒介导增强型绿色荧光蛋白基因在兔骨髓间充质干细胞中的表达,及转染后干细胞活性的变化,以寻找稳定标记兔骨髓间充质干细胞的方法. 设计、时间及地点:细胞学体外观察,于2008-03/05在南京市第一医院骨科干细胞实验室完成. 材料:健康2月龄纯种新西兰大白兔4只,由南京医科大学实验动物基地提供.重组腺病毒Ad5/F35-EGFP为北京本元正阳基因有限公司产品. 方法:用密度梯度离心法分离纯化兔骨髓间充质干细胞,贴肇法纯化扩增.取传至第4代细胞,流式细胞仪检测细胞标志的表达,消化离心重悬后进行计数,平均分成5组,每组细胞数5.0×105个,接种于25 m2培养瓶,空白组加入50 μL的PBS液,剩余4组加入重组腺病毒Ad5/F35-EGFP进行转染,感染复数(MOI)分别为10,20,50,100,继续传代培养.主要观察指标:骨髓间充质干细胞的生长状态及表面标志鉴定,转染后骨髓间充质干细胞增强型绿色荧光蛋白的表达及活性变化.结果:原代培养48 h后见细胞贴壁,8 d时细胞铺满瓶底80%以上,绝大多数呈梭形,传代后细胞增殖速度加快,三四天即可传代,第4代细胞CD29和CD44呈阳性表达,CD34与CD45呈阴性表达.转染后24 h可见绿色荧光,7 d时荧光最强,细胞转染率与感染复数值的呈线性增长关系,至49 d时仍可见绿色荧光.转染后0,7,14,28,49 d,感染复数=50组的骨髓间充质干细胞数量均与空白组基本相似(P均>0.05),即转染后细胞增殖能力无明显变化. 结论:重组腺病毒载体能高效标记骨髓间充质干细胞,感染复数为50时较为理想,增强型绿色荧光蛋白基因可持续表达49 d,且标记后不影响骨髓间充质干细胞的增殖活性.     

肾上腺髓质素真核表达载体对皮瓣缺血再灌注损伤的影响

背景:肾上腺髓质素可在心、脑、肾、肝等器官的缺血再灌注过程中起保护作用.目的:观察肾上腺髓质素真核表达载体对大鼠腹部皮瓣缺血再灌注损伤的影响及其作用机制.方法:构建大鼠肾上腺髓质素真核表达载体,将SD大鼠随机分假手术组、模型组、维拉帕米组、重组质粒组.重组质粒组腹部皮内注射肾上腺髓质素真核表达载体,其余各组注射等量生理盐水,各组注射4次后建立缺血再灌注模型,维拉帕米组于皮瓣内注射维拉帕米.结果与结论:与模型组相比,重组质粒组皮瓣组织中丙二醛、血管内皮素1的含量分别降低了38.50%(P < 0.01),54.73% (P < 0.01),超氧化物歧化酶的含量增加了50.67%(P < 0.05).皮瓣组织学检查结果显示重组质粒组皮瓣炎性细胞浸润与水肿程度也较模型组明显减轻.结果证实肾上腺髓质素真核表达载体对大鼠皮瓣缺血再灌注损伤具有保护作用,其机制与减轻脂质过氧化及减少炎症细胞浸润有关.     

肾上腺髓质素真核表达载体对皮瓣缺血再灌注损伤的影响

背景：肾上腺髓质素可在心、脑、肾、肝等器官的缺血再灌注过程中起保护作用。目的：观察肾上腺髓质素真核表达载体对大鼠腹部皮瓣缺血再灌注损伤的影响及其作用机制。方法：构建大鼠肾上腺髓质素真核表达载体,将SD大鼠随机分假手术组、模型组、维拉帕米组、重组质粒组。重组质粒组腹部皮内注射肾上腺髓质素真核表达载体,其余各组注射等量生理盐水,各组注射4次后建立缺血再灌注模型,维拉帕米组于皮瓣内注射维拉帕米。结果与结论：与模型组相比,重组质粒组皮瓣组织中丙二醛、血管内皮素1的含量分别降低了38.50%（P〈0.01）,54.73%（P〈0.01）,超氧化物歧化酶的含量增加了50.67%（P〈0.05）。皮瓣组织学检查结果显示重组质粒组皮瓣炎性细胞浸润与水肿程度也较模型组明显减轻。结果证实肾上腺髓质素真核表达载体对大鼠皮瓣缺血再灌注损伤具有保护作用,其机制与减轻脂质过氧化及减少炎症细胞浸润有关。     

Adrenomedullin reduces Staphylococcus aureus alpha-toxin-induced rat ileum microcirculatory damage

OBJECTIVE: Increased microvascular permeability and perfusion mismatch are hallmarks of sepsis or septic shock. The intestinal mucosa is very sensitive to tissue hypoxia. Intestinal mucosa dysfunction may allow translocation of bacteria and their products, thereby perpetuating sepsis and inflammation. Staphylococcus aureus alpha-toxin is a major pathogenicity determinant of this bacterium, provoking cardiovascular collapse. Current evidence suggests that the endogenous peptide adrenomedullin stabilizes circulatory homeostasis in systemic inflammatory response. Using alpha-toxin as a well-defined strong initiator of an inflammatory reaction, we tested the hypothesis that exogenously applied adrenomedullin stabilizes gut microcirculation. DESIGN: Prospective, experimental study. SETTING: Research laboratory at a university hospital. SUBJECTS: Isolated, perfused ileum from male Sprague-Dawley rats and human umbilical vein endothelial cells. INTERVENTIONS: Administration of S. aureus alpha-toxin before or after infusion of adrenomedullin. MEASUREMENTS AND MAIN RESULTS: Injection of a bolus of 1 microg of alpha-toxin in the superior mesenteric artery in a constant-flow, blood-perfused preparation of rat ileum increased perfusion pressure and relative hemoglobin concentration and decreased mucosal hemoglobin oxygen saturation. Continuous infusion of adrenomedullin (0.1 micromol/L) significantly reduced these alpha-toxin-related effects. Severe microvascular hyperpermeability observed in alpha-toxin-exposed ileum was abolished by adrenomedullin pretreatment. In addition, adrenomedullin blocked alpha-toxin-induced endothelial myosin light chain phosphorylation, endothelial cell contraction, and subsequent loss of endothelial barrier function in vitro. Treatment of alpha-toxin (infusion of 0.05 microg/mL)-exposed ileum with adrenomedullin (0.1 micromol/L) started 10 mins after onset of toxin application also significantly reduced superior mesenteric artery pressure and permeability increase. CONCLUSIONS: In summary, these data suggest that exogenous adrenomedullin protects ileum by reducing alpha-toxin-induced microcirculatory disturbances and by stabilizing endothelial barrier function.     

大鼠局灶性脑缺血再灌注后血浆肾上腺髓质素的表达及与内皮素的关系

目的：探讨大鼠局灶性脑缺血再灌注后血浆肾上腺髓质素含量的变化及其与内皮素的相互关系。方法：54只SD大鼠分为正常组（A组）6只、假手术组（B组）6只和模型组（C组）42只。C组大鼠制作成局灶性脑缺血2h再灌注模型并应用放射免疫分析法检测不同时间段血浆肾上腺髓质素和内皮素的含量，同时与A、B组进行比较分析。结果：C组再灌注后血浆肾上腺髓质素和内皮素的含量均升高，与A、B组比较，差异有显著性意义（均P〈0．01）。肾上腺髓质素的含量与大鼠局灶性神经功能缺损症状的严重程度、梗死体积及内皮素含量均呈显著正相关（均P〈0．01），且高峰值出现在缺血再灌注后2h，随后逐渐下降，约166h又有所上升，但与A、B组比较仍差异有显著性意义（P〈0．01）。结论：局灶性脑缺血再灌注后血浆肾上腺髓质素含量变化可有助于判断病情严重程度、梗死灶的体积大小及病情预后。     

Transgenic mice with ocular overexpression of an adrenomedullin receptor reflect human acute angle-closure glaucoma

Glaucoma, frequently associated with high IOP (intra-ocular pressure), is a leading cause of blindness, characterized by a loss of retinal ganglion cells and the corresponding optic nerve fibres. In the present study, acutely and transiently elevated IOP, characteristic of acute angle-closure glaucoma in humans, was observed in CLR (calcitonin receptor-like receptor) transgenic mice between 1 and 3 months of age. Expression of CLR under the control of a smooth muscle alpha-actin promoter in these mice augmented signalling of the smooth-muscle-relaxing peptide adrenomedullin in the pupillary sphincter muscle and resulted in pupillary palsy. Elevated IOP was prevented in CLR transgenic mice when mated with hemizygote adrenomedullin-deficient mice with up to 50% lower plasma and organ adrenomedullin concentrations. This indicates that endogenous adrenomedullin of iris ciliary body origin causes pupillary palsy and angle closure in CLR transgenic mice overexpressing adrenomedullin receptors in the pupillary sphincter muscle. In human eyes, immunoreactive adrenomedullin has also been detected in the ciliary body. Furthermore, the CLR and RAMP2 (receptor-activity-modifying protein 2), constituting adrenomedullin receptor heterodimers, were identified in the human pupillary sphincter muscle. Thus, in humans, defective regulation of adrenomedullin action in the pupillary sphincter muscle, provoked in the present study in CLR transgenic mice, may cause acute and chronic atony and, thereby, contribute to the development of angle-closure glaucoma. The CLR transgenic mice used in the present study provide a model for acute angle-closure glaucoma.     

Effects of adrenomedullin on acute ischaemia-induced collateral development and mobilization of bone-marrow-derived cells

Adrenomedullin exerts not only vasodilatory effects, but also angiogenic effects. In the present study, we investigated the effects of adrenomedullin on collateral formation and circulating bone-marrow-derived cells after acute tissue ischaemia. Bone marrow of 8-10-week-old female C57BL/6J mice was replaced with that from GFP (green fluorescent protein) transgenic mice (GFP mice). At 8 weeks after transplantation, hindlimb ischaemia was induced by resecting the right femoral artery and a plasmid expressing human adrenomedullin (50 mug) was injected into the ischaemic muscle, followed by in vivo electroporation on a weekly basis. Overexpression of adrenomedullin significantly enhanced the blood flow recovery compared with controls (blood flow ratio, 1.0+/-0.2 compared with 0.6+/-0.3 respectively, at week 4; P<0.05) and increased capillary density in the ischaemic leg as determined by anti-CD31 immunostaining of the ischaemic muscle (567+/-40 compared with 338+/-65 capillaries/mm(2) respectively, at week 5; P<0.05). There were more GFP-positive cells in the thigh muscle of the mice injected with adrenomedullin than in that of the control mice (29.6+/-4.5 compared with 16.5+/-3.3 capillaries/mm(2) respectively, at week 5; P<0.05). We repeated the same experiments using LacZ-knock-in mice instead of GFP mice, and obtained similar results. These findings suggest that adrenomedullin may augment ischaemia-induced collateral formation with some effects on circulating bone-marrow-derived cells.     

PCI-hTGF-β1转染体外培养成人退变椎间盘细胞及其表达产物的测定

背景:人转化生长因子β1基因可用于椎间盘退变的基因治疗,但有效载体的构建是实验的关键。目的:测定真核表达载体PCI-hTGF-β1转染体外培养成人退变椎间盘细胞可否表达产物人转化生长因子β1,为椎间盘退变的基因治疗提供实验基础。设计:单一样本实验。单位:山东省创伤骨科研究所,一所市立医院骨科。材料:实验于1999-10/2001-01在山东省创伤骨科研究所实验室进行。椎间盘标本均为椎间盘突出症患者手术中取材(获患者知情同意)。标本1为30岁女性的L45/椎间盘,标本2为38岁女性的L5/S1椎间盘。方法:①培养成人退变椎间盘细胞:标本离体30min内取回实验室,收集原代培养的纤维环细胞和髓核细胞。②转染:将细胞置于24孔培养板中,每孔细胞数目在5.5×105个,应用构建的PCI-hTGF-β1真核表达载体对其进行转染,并设立转染PCI组和未转染组。③用免疫组织化学方法对转染48h后的细胞进行表达产物测定。主要观察指标:两个标本中,各组原代纤维环细胞和髓核细胞中真核表达载体PCI-hTGF-β1的阳性细胞产物的吸光度值比较。结果:①标本1:原代纤维环细胞和原代髓核细胞中真核表达载体PCI-hTGF-β1的阳性细胞产物的吸光度值为PCI组的3.49,3.69倍,为未转染组的3.55倍。②标本2:原代纤维环细胞和原代髓核细胞中真核表达载体PCI-hTGF-β1的阳性细胞产物的吸光度值为PCI组的3.56,3.46倍,为未转染组的3.43,3.33倍。结论:PCI-hTGF-β1是人转化生长因子β1基因在体外培养退变椎间盘细胞转染中有效的真核表达载体,可以成功转染体外培养的成人退变椎间盘细胞,并可获得人转化生长因子β1基因产物的高表达。     

Proadrenomedullin NH(2)-terminal 20 peptide, a new product of the adrenomedullin gene, inhibits norepinephrine overflow from nerve endings.

Proadrenomedullin NH(2)-terminal 20 peptide (PAMP) and adrenomedullin, which are derived from proadrenomedullin, exhibit remarkable hypotensive action. We investigated the effect of PAMP and adrenomedullin on peripheral sympathetic neutral transmission. Using perfused rat mesenteric arteries, PAMP (0, 1, 5, and 10 pmol/ml) decreased norepinephrine overflow by periarterial electrical nerve stimulation in a dose-dependent fashion (0.244 +/- 0.043, 0.231 +/- 0.048, 0.195 +/- 0.061 and 0.168 +/- 0.051 ng/gram tissue weigh: NS, P < 0.05, and P < 0.02, respectively). In contrast to PAMP, adrenomedullin (1, 5, and 10 pmol/ml) did not change it. In contrast, vasoconstrictive response of mesenteric arteries to exogenous norepinephrine was significantly attenuated by 10 pmol/ml of adrenomedullin but not by the same dose of PAMP. Calcitonin gene-related peptide (8-37) [CGRP(8-37)], a CGRP receptor antagonist, inhibited the vasodilatory effect of adrenomedullin but could not suppress the sympathoinhibitory effect of PAMP. Neither a nicotinic antagonist, hexamethonium, nor a presynaptic alfa2 antagonist, yohimbine, blocked the sympathoinhibitory effect of PAMP. Thus, it suggests that PAMP and adrenomedullin, which are derived from the same gene, exhibit different hypotensive mechanisms: PAMP inhibits neural transmission at peripheral sympathetic nerve ending, although adrenomedullin directly dilates vascular smooth muscle, possibly through CGRP-like receptor.     

Adrenomedullin from a pheochromocytoma to the eye: implications of the adrenomedullin research for endocrinology in the 21st century

In the last several decades, the concept of "endocrinology" has been greatly changed. One major change was due to the discovery of peptide hormones secreted by the organs that were not "classical" endocrine organs. For example, corticotropin-releasing hormone and many neuropeptides are secreted by the neurons, atrial natriuretic peptide by the heart, endothelin-1 by the vascular endothelial cells, and leptin by the adipose tissues. Now, the brain, heart, vascular tissue and adipose tissue can be considered to be endocrine organs. Cardiovascular diseases and obesity are therefore important targets of the endocrine research. Adrenomedullin is a potent vasodilator peptide consisting of 52 amino acids. It was originally discovered from a human pheochromocytoma, and belongs to the calcitonin gene-related peptide (CGRP) family. Adrenomedullin is produced and secreted by various types of cells, for example, vascular endothelial and smooth muscle cells, cardiomyocytes, fibroblasts, macrophages, neurons, glial cells, and retinal pigment epithelial cells. Such ubiquitous expression has not been observed in other neuropeptides, including neuropeptide Y and CGRP. Expression of adrenomedullin is induced by hypoxia and proinflammatory cytokines. In addition to vasodilator actions, this peptide has central inhibitory actions on water drinking and salt appetite, effects on the secretion of some hormones and cytokines, inotropic actions and effects on cell growth and apoptosis. Adrenomedullin is produced by various non-endocrine tumors, as well as endocrine tumors, and acts as a growth stimulatory factor for the tumor cells. Adrenomedullin seems to be involved in the pathophysiology of many diseases, including ischemic heart diseases, inflammatory diseases, tumors, and even eye diseases. The adrenomedullin research implies that "the neuroendocrine system" exists in much broader types of cells than previously thought, and that the endocrine research is able to contribute to the understanding of the pathophysiology of many diseases.