骨髓间充质干细胞静脉移植对心肌梗死大鼠心功能的影响

目的探讨静脉途径移植骨髓间充质干细胞(MSCs)对急性心肌梗死(AMI)大鼠心功能的影响。方法雄性SD大鼠20只,分为干细胞移植组(10只)和对照组(10只)。结扎大鼠左冠状动脉建立心肌梗死模型。同种异体大鼠MSCs体外分离、纯化、扩增,4’,6-二脒-2-苯基吲哚(4’,6-diamidino-2-phenylindole,DAPI)标记,并通过尾静脉于心肌梗死后1周移植入AMI大鼠体内,对照组则注射等量培养液。4周后测定心功能,并行免疫组织化学检测。结果心肌梗死4周后,干细胞移植组心肌组织冷冻切片中可以观察到DAPI标记细胞存在,免疫组织化学显示阳性标记细胞a-Actin肌动蛋白检测阳性。干细胞移植组心功能较对照组有明显改善(P<0.05)。结论MSCs经静脉移植可以归巢至梗死心肌处,并能改善受损的心功能。     

同种异体骨髓间充质干细胞在大鼠心脏的迁移及分化特点

目的探讨同种异体骨髓间充质干细胞(MSCs)在大鼠心脏定居存活情况、同种异体移植是否可行?正常心脏微环境与梗死心脏微环境对骨髓间充质干细胞(MSCs)迁移、分化的影响.方法将体重200～250g雌性大鼠35只随机分为4组①正常心脏+rMSCs移植组(Control+rMSCs,n=10)正常大鼠接受同种异体rMSCs移植治疗(5×106MSCs/100 ul,分4点注入);②急性心肌梗死对照组(AMI,n=10)大鼠心肌梗死后注射等量培养基;③心肌梗死+rMSCs移植组(AMI+rMSCs,n=10)大鼠心肌梗死后1～3h接受同种异体rMSCs移植治疗(5×106MSCs/100ul,分4点注入);④单个核细胞治疗组(n=5)大鼠心肌梗死后1-3h接受同种异体单个核细胞移植治疗(5×106MSCs/100μl,分4点注入).结扎左冠状动脉前降支造成心肌梗死模型.用比重1.073的Percoll分离液分离来自雄性Wistar大鼠骨髓MSCs,经贴壁、及时传代纯化MSCs;用FITC或PE标记的表面分子CD34、CDlla、CD71、CD29抗体对二代MSC进行流式细胞术鉴定;采用01ivette方法结扎冠状动脉建立急性心肌梗死模型,经DAPI标记移植细胞(MSCs、单个核细胞),分别置入到各组大鼠心脏组织,模拟同种异体细胞移置治疗.于细胞移植后10周取心脏,荧光显微镜下直接观察植入细胞迁移分布;免疫荧光检测心肌特异蛋白(肌钙蛋白、转录因子4和连接蛋白43)抗原表达.结果(1)采用密度为1.073的percoll分离液分离MSCs,形态呈较均一的长梭形,由原代的(5.0±0.21)×105个MSCs,经扩增16代后可获得(4.0±0.36)×1012个细胞,扩增约(6.8±0.45)×106倍,形态均一并保持原有特性.(2)流式细胞术鉴定,扩增二代的MSCs强表达CD90(动物干细胞表面标志),其阳性达97.27%,不表达CD45(白细胞分化抗原)和CD31(内皮细胞表面标志),CD44(黏附分子)仅有微弱表达(2,72%),这表明MSCs是骨髓中区别于造血干细胞的一群处于未分化状态的非定向干细胞.(3)经纯化的大鼠MSCs在同种异体大鼠心脏可定居、生存,而未经纯化的单个核细胞移植在同种异体大鼠心脏未见存活;(4)在正常心脏微环境中,带蓝色荧光的供体MSCs细胞核呈小岛屿状分布,与宿主心肌纤维排列无关;而在心肌梗死模型大鼠心脏微环境中,蓝色细胞核分布广泛,形态呈椭圆形类似心肌细胞核,并与宿主心肌纤维排列方向一致,免疫组化检测胞浆心肌特异蛋白染色阳性.结论及时传代可避免大鼠MSCs自身分化,也是纯化大鼠MSCs的重要因素之一;纯化的MSCs具有免疫耐受特性,无需加用免疫抑制剂,可进行同种异体移植;同种异体MSCs在正常心脏微环境中不发生迁移、分化;而在急性梗死大鼠心脏中具有向缺血梗死区迁移并分化为心肌样细胞的特点.针对慢性心肌梗死瘢痕的治疗,Bittira发现移植诱导后的MSCs较未诱导的MSCs更利于瘢痕局部心肌分化,今后需要阐明MSCs定向分化的分子机制,还需要在增加移植细胞存活率、心肌细胞分化率及功能化研究等方面取得突破,推动MSCs治疗心肌梗死、慢性心功能不全的研究工作,对未来MSCs移植应用于临床具有十分重要的意义.     

同种异体移植骨髓间充质干细胞治疗大鼠心肌梗死

目的　探讨同种异体骨髓间充质干细胞 (MSCs)在梗死大鼠心脏局部存活、迁移、分化及对心功能的影响 ;明确同种异体细胞移植治疗心肌梗死 (MI)的可行性及效果。方法　雌性Wistar大鼠 3 5只 ,随机分为正常对照组、急性心肌梗死 (AMI)组及MI MSCs治疗组。分离纯化雄性Wistar大鼠骨髓MSCs ,于左冠状动脉前降支结扎后 1～ 3h植入到雌性大鼠心脏组织 ,移植后 10周检测心功能并取心脏检测各种相关指标。结果　异体大鼠MSCs经纯化后可在梗死心脏组织定居、生存 ,并与宿主心肌纤维排列方向一致 ,免疫组化检测胞质心肌特异蛋白染色阳性 ,与MI组比较 ,异体细胞移植组左室收缩压升高 (P <0 0 5) ,舒张末压明显降低 (P <0 0 1)、左心室内压最大上升和下降速率显著增快 (P <0 0 5) ,梗死边缘区心肌面毛细血管数目明显增加 (P <0 0 5) ,多功能真彩色病理图像分析系统显示MI面积缩小 (P <0 0 5)。结论　同种异体MSCs移植治疗MI可行、有效     

经冠脉自体骨髓干细胞移植改善左室重构机制的研究

目的研究自体骨髓单个核细胞(BM-MNC)和间充质干细胞(MSCs)移植对急性心肌梗死(AMI)后心室重构的影响,探讨不同干细胞移植对心室重构影响的机理。方法以小型猪为研究对象,通过球囊导管压迫冠状动脉前降支的方法,建立小型猪AMI动物模型。在AMI 90 min时,经冠状动脉腔内进行自体BM-MNC和MSCs移植。于术前及干细胞移植后28 d,观察心功能、心肌微血管计数、心肌核因子_KB、心肌细胞凋亡、心肌血管内皮生长因子(VEGF)和碱性成纤维细胞生长因子(bFGF)的mRNA表达。与心功能进行相关性分析。结果(1)术后28 d,BM-MNC组、MSCs组EDD均明显低于AMI模型组(P=0.005),EF明显高于模型组(P=0.0001;P=0.0017)。(2)BM-MNC移植组血管数比梗死组及MSCs组增加(梗死区P=0.000 1,边缘区P=0.000 1)。(3)BM-MNC组及MSCs组心肌细胞凋亡率比梗死模型组减少(梗死区P=0.000 1,梗死边缘区P= 0.000 1,正常区P=0.005 2)。(4)BM-MNC组及MSCs组NF-_KB阳性率比单纯AMI模型组显著降低(P=0.001)。(5)梗死模型组、BM-MNC组以及MSCs组的梗死区及梗死边缘区的VEGF基因表达量与正常对照组的相比增加(梗死区P=0.0001;梗死边缘区P=0.000 1)。BM-MNC及MSCs移植组,心肌梗死区的bFGF基因表达量比梗死模型组及正常对照组均显著增加(P=0.000 1)。LVEF与心肌细胞凋亡呈负相关(r=-0.441 1,P= 0.027 3),与心肌NF-_KB负相关(r=-0.579 6,P=0.000 6);与梗死区、边缘区血管数正相关(r=0.775 0,P=0.000 3);与VEGF表达正相关(r= 0.565 1,P=0.018 1);与bFGF表达正相关(r=0.573 5,P=0.016 1)。结论经冠脉自体BM-MNC及MSCs移植均可减轻心肌梗死后左心室重构,改善急性心肌梗死后心功能,增加心肌血管数量,增加梗死区及梗死边缘区VEGF及bFGF表达,减少心肌细胞凋亡。心功能的改善与干细胞移植后增加心肌血管数量、增加心肌VEGF及bFGF表达、减少心肌细胞凋亡以及减少心肌组织NF-_KB水平有关。     

缺血预处理间充质干细胞移植治疗心肌梗死实验研究

目的探讨静脉移植缺血预处理的间充质干细胞（MSCs）对梗死心肌的修复作用。方法选择纯种大白兔46只制作心肌梗死模型,分为缺氧预处理MSCs移植组（A组）、非缺氧预处理MSCs移植组（B组）和对照组,于心肌梗死后30d分别检测心功能、梗死心肌的形态学变化以及新生毛细血管密度。结果与对照组比较,A、B组左心室收缩末期内径、舒张末期内径降低,心功能提高,室壁厚度增加,心肌梗死面积缩小,梗死区和梗死边缘区新生毛细血管密度增加（P〈0．05）。结论MSCs移植治疗兔心肌梗死可改善心功能、缩小梗死面积、增加梗死心肌新生毛细血管密度,经缺氧预处理的MSCs移植治疗更有优势。     

曲美他嗪预处理BMSCs移植对心肌缺血再灌注大鼠心功能改善的影响

目的探讨曲美他嗪(TMZ)预处理骨髓间充质干细胞(BMSCs)移植到缺血再灌注(I/R)微环境下细胞生存及对心功能改善的影响。方法将TMZ预处理或未预处理的BMSCs与心肌细胞H/R上清液共培养,采用CCK-8法检测细胞活性、RT-PCR检测Bcl-2、Bax的基因表达水平。32只SD大鼠随机分为假手术组(Sham组)、心肌I/R组、干细胞移植组(BMSCs组)及TMZ预处理干细胞移植组(BMSCs+TMZ组)。建立大鼠心肌缺血再灌注模型,当再灌注平稳后于损伤心肌边缘注入干细胞(细胞数5×105)。1 w后用荧光显微镜观察BMSCs存活数,4 w后应用超声心动图评估心功能,TTC法检测梗死面积,Western印迹分析移植周围区域Bcl-2及Bax的蛋白表达。结果 BMSCs与心肌细胞H/R上清液共培养后细胞活性显著下降,但TMZ预处理后使其下降趋势得到明显逆转。RT-PCR结果表明,与未预处理BMSCs相比,在TMZ预处理BMSCs中,Bcl-2基因表达水平上调,Bax基因表达水平下调。在体内,术后1 w,BMSCs+TMZ组每个高倍镜下双标记细胞数显著高于BMSCs组。术后4 w,BMSCs+TMZ组和BMSCs组均较I/R组心功能明显改善,心肌梗死面积缩小;两组间进一步比较,BMSCs+TMZ组表现出了更进一步的心功能改善与更小的心肌梗死面积。Western印迹结果表明,与未预处理BMSCs相比,在TMZ预处理BMSCs组中,Bcl-2表达上调,Bax蛋白下调。结论血运重建联合TMZ预处理BMSCs移植治疗急性心肌梗死增加BMSCs存活和心功能的恢复上优于单纯BMSCs移植,可能通过上调Bcl-2及下调Bax的表达而发挥抗凋亡作用。     

Bcl-2改善老年人骨髓间充质干细胞抗缺氧损伤能力的研究

目的:通过转染Bcl-2基因增强老年人骨髓间充质干细胞(hMSCs)的Bcl-2表达,尝试改善老年hMSCs在缺氧环境下的抗凋亡、抗损伤能力,为基因联合细胞移植改善老年hMSCs自体移植治疗缺血性心脏病的提供依据。方法:分离培养老年hMSCs并进行鉴定。构建Bcl-2基因质粒并对老年人hMSCs进行Bcl-2基因的转染。应用CO_2和N_2的混合气体建立稳定的缺氧培养环境模拟心肌梗死时的缺氧环境,分别对老年hMSCs及Bcl-2转染后老年hMSCs进行缺氧培养,比较各组细胞的细胞凋亡及损伤情况。通过冠状动脉结扎建立稳定的大鼠心肌梗死模型,分别应用老年hMSCs及Bcl-2转染后的老年hMSCs进行细胞移植,比较各组细胞在心肌梗死区域缺氧环境下的存活情况,同时应用超声心动图对比两组细胞移植后心肌梗死大鼠心脏功能的改善情况。结果:转染Bcl-2的老年hMSCs能够稳定表达Bcl-2的基因及蛋白。转染Bcl-2后的老年hMSCs在缺氧环境下较未转染的老年细胞其凋亡数量明显下降、生存率明显提高,表达的Bcl-2基因及蛋白也多于未转染的老年细胞。各组细胞移植至大鼠梗死心脏后可见转染Bcl-2的老年hMSCs组的细胞存活数量明显高于未转染组,梗死心脏的Bcl-2的基因含量和蛋白表达量也高于未转染老年细胞移植组,心肌梗死大鼠在移植了转染Bcl-2的老年hMSCs组后其心脏的射血分数和左心室短轴缩短率好于未行细胞移植组和移植未转染细胞组。结论:增加老年hMSCs中Bcl-2基因的含量能够增加其Bcl-2蛋白表达量、增强其在缺氧环境中的抗凋亡能力。应用Bcl-2转染的方法能够增强老年hMSCs移植治疗心肌梗死时的移植后细胞存活能力、提高梗死区域的Bcl-2蛋白表达量并增强了老年hMSCs移植改善心肌梗死后心脏功能的效果。     

诱导多能干细胞移植治疗对心肌梗死模型小鼠心功能的影响

目的探讨诱导多能干细胞(i PSCs)移植治疗对急性心肌梗死(AMI)小鼠心功能的影响。方法体外培养i PSCs、心肌细胞,采用结扎法建立AMI模型,并随机分为AMI组、AMI+i PSCs组、AMI+心肌细胞(CM)组,正常小鼠为对照(NC)组,每组12只。结扎后30 min移植相应细胞于梗死区域,分别于移植后1 h、1 d、7 d、14 d、21 d记录小鼠心率、血压变化,分别于移植后1 h、1 d、2 d、5 d及7 d时记录小鼠心电图,移植后第21天采用免疫组化染色检测各组心肌缝隙连接蛋白(Cx)-43的表达。结果细胞移植第14天后,AMI+i PSCs组心率明显低于同时间点的AMI+CM组、AMI组及NC组(P0.05);细胞移植后第2天、第5天及第7天时,AMI+i PSCs组ST段抬高程度较AMI组明显降低(P0.05);与NC组相比,AMI+i PSCs组血压无明显下降(P0.05);移植后第21天,AMI+i PSCs组Cx-43表达明显高于AMI组(P0.05)。结论 i PSCs移植治疗可改善心肌梗死小鼠心功能,并使梗死区Cx-43的表达增加。     

左卡尼汀提高大鼠心肌梗死后移植骨髓间充质干细胞的存活和作用

目的探讨左卡尼汀（LC）是否能提高心肌梗死后移植骨髓间充质干细胞（MSCs）的存活率,从而提高其疗效。方法60只大鼠随机分为5组：假手术组、模型组、LC组、MSCs组和左卡尼汀联合骨髓间充质干细胞（LC＋MSCs）组。4周后检测心功能、MSCs存活情况和梗死区心肌纤维化水平。结果4周后,与MSCs组比较,LC＋MSCs组MSCs的存活、左室心功能、心肌纤维化均改善（P〈0．05）。结论LC联合MSCs使用可提高MSCs的存活率,更好地改善心肌梗死后的心功能和心肌纤维化。     

骨髓间充质干细胞不同移植方法对心肌梗死大鼠心脏的保护作用

目的对比研究经尾静脉和心外膜直视注射移植骨髓间充质干细胞（MSCs）对心肌梗死大鼠的心脏保护作用。方法结扎左冠状动脉前降支制备大鼠心肌梗死模型,采用同种异体MSCs体外分离、纯化、培养和标记,在梗死后2周,A组经尾静脉植入MSCs,B组心外膜直视注射MSCs,C组尾静脉注入等量DMEM培养液为对照。4周后测定心功能,并行免疫组织化学检测。结果移植组心肌组织中可以观察到DAPI标记细胞存在,免疫组化显示阳性标记细胞α-Actin肌动蛋白检测阳性。与对照組相比,A和B组左心功能显著改善（P<0.05）,A和B组梗死面积明显缩小[分别为（45±2）%,（40±4）%和（41±3）%,P<0.05]。结论MSCs经静脉移植和心外膜植入都能够归巢至心肌梗死区,对梗死大鼠的心脏都具有保护作用。     

A Reconstituted In Vitro Clot Model for Evaluating Laser Thrombolysis

Background/Objective: Laser thrombolysis is the selective removal of thrombus from occluded blood vessels using laser energy. A reconstituted clot model with reproducible optical absorption properties was developed to evaluate the effect of various laser parameters on thrombus removal rate. Study Design/Materials and Methods: Reconstituted clots were made with known fibrinogen concentrations and hematocrits. Ex vivo clots were collected from ten swine. Four red gelatin phantoms were prepared. Mass removal rates and ablation efficiencies were determined using a 577 nm, 1 sec pulsed dye laser. The ablation efficiencies of the three clot models were compared at an energy of 25 mJ and a repetition rate of 4 Hz. In addition, the reconstituted clot model was ablated as pulse energy and repetition rate were varied with average power held constant at 100 mW. Results: The mean ablation efficiency for ex vivo clots ranged from 0.4 ± 0.1 to 3.4 ± 0.7 g/mJ/pulse, with significant differences between groups (ANOVA p < 0.05). Reconstituted clots of varied fibrinogen content had ablation efficiencies of 1.5 ± 0.2 to 1.6 ± 0.3 g/mJ/pulse at this energy and repetition rate. Gelatin ablation efficiency was inversely proportional to protein content and ranged from 0.5 ± 0.3 to 2.0 ± 0.7 g/mJ/pulse. Reconstituted clot mass removal rates (in g/s) were clinically similar for settings ranging from 13 mJ at 8 Hz to 33 mJ at 3 Hz. Conclusions: The reconstituted model clot is a reproducible and biologically relevant thrombolysis target. Ex vivo clot lacks reproducibility between individuals and gelatin phantoms lack clinical relevance. At a constant average power, varying laser parameters did not affect mass removal rates to a clinically significant degree.     

In Vivo Canine Model Comparison of Cardiovascular Effects of Antidepressants Milnacipran and Imipramine

Milnacipran is a specific serotonin and norepinephrine reuptake inhibitor, which has been widely used against major depressive episodes. In this study, cardiovascular effects of milnacipran were assessed in comparison with those of a typical tricyclic antidepressant imipramine using the halothane-anesthetized dogs. Milnacipran (n = 6) or imipramine (n = 6) was intravenously administrated in three escalating doses of 0.1, 1 and 10 mg/kg over 10 min with a pause of 20 min between the doses. Clinically relevant plasma concentrations were obtained after 0.1–1 mg/kg of milnacipran in this study, whereas therapeutic dose and plasma concentration of imipramine were reported to be similar to those of milnacipran. The low and middle doses of milnacipran hardly affected cardiohemodynamic or electrophysiological variables except that they slightly increased vascular tone and ventricular contraction, whereas same doses of imipramine delayed repolarization process without affecting the other variables. The high dose of both milnacipran and imipramine induced similar extent of negative chronotropic, inotropic and dromotropic effects together with vasoconstriction and repolarization delay. Thus, the effects of milnacipran may be more selective for cardiohemodynamics than for repolarization delay, whereas reverse will be true for imipramine, supporting lack of clinical report of patients with milnacipran-induced long QT syndrome unlike imipramine.     

微小隐孢子虫感染犬肾细胞模型的建立及生长发育过程的研究

目的 建立微小隐孢子虫体外感染犬肾细胞（MDCK细胞）模型, 并观察其生长发育过程。 方法 利用MDCK细胞为隐孢子虫感染对象, 优化隐孢子虫感染MDCK细胞的培养条件, 观察隐孢子虫在MDCK细胞中的生长发育过程。将体外感染48 h的细胞培养上清接种小鼠, 观察其感染情况。 结果 在含有5%胎牛血清的DMEM培养基中, 用1×10⁵隐孢子虫卵囊感染2.0×10⁵个MDCK细胞, 培养12 h为最佳培养条件。在感染后72 h内, 隐孢子虫出现连续发育阶段, 包括脱囊、子孢子、裂殖子、裂殖体、滋养体、配子体、合子、薄壁卵囊和厚壁卵囊, 在60～72 h内形成卵囊;用感染48 h的细胞培养上清接种于免疫抑制小鼠, 10 d后有隐孢子虫卵囊排出。 结论 建立了能稳定用于微小隐孢子虫体外感染的MDCK细胞模型, 观察到隐孢子虫的生长发育全过程。     

A Model for In Vivo Validation of Linear Lesions in the Right Atrium

Linear lesions have been proposed for treatment of complex atrial arrhythmias including atrial macroreentry tachycardia and compartmentalization in atrial fibrillation. Aim: To judge the effectiveness of a given lesion design, definite endpoints are necessary to ascertain the completeness of the line of block produced. Methods and results: We report validation criteria for long linear lesions in the right atrium in 42 pts, that combine both conventional and 3D mapping information (CARTO). Transferring from the validation of bi-directional block of the cavotricuspid isthmus line for atrial flutter, we validated 2 additional long linear lesions in the right atrium (anterior line and intercaval line). In addition to a complete isthmus line in all 42 pts, in 28 pts a complete anterior line was achieved and validated by both conventional and CARTO criteria. A complete intercaval line was deployed in 11 pts with complete anterior and isthmus lines (with a characteristic shift for the intercaval line) and in 5 pts without a complete anterior line (without characteristic shift). Conclusions: Conventional catheters placed at strategic locations on opposite sides of the intended ablation line, can depict a sudden characteristic change in the activation sequence. Using a combination of both techniques, deployment and validation of long linear lesion can be facilitated.     

An In Vitro Model for Studying Neuromuscular Transmission in the Mouse Pharynx

The muscles of the pharynx are controlled by networks of neurons under the control of specific regions in the brain stem, which have been fairly well studied. However, the transmission between these neurons and the pharyngeal muscles, at the motor end plates, is less well understood. Therefore, an in vitro model for the study of neuromuscular transmission in the pharyngeal muscle of the mouse was developed. Ring preparations from the inferior constrictor and the cricopharyngeus muscles were isolated and mounted for isometric force recording at physiologic temperature. Preparations from the diaphragm and the soleus muscles were examined in parallel. The muscles were stimulated at supramaximal voltage with short tetani at 100 Hz. Following direct stimulation of the muscle fibers, using a longer pulse duration, the rate of force development of the pharyngeal muscles was similar to that of the diaphragm and faster than that of the soleus muscle. By varying the duration of the stimulation pulses, conditions where the nerve-mediated activation contributed to a major extent of the contractile responses were identified. Gallamine completely inhibited the nerve-mediated responses. In separate experiments the dose dependence of gallamine inhibition was examined, showing similar sensitivity in the inferior pharyngeal constrictor compared to the diaphragm and soleus muscles. We conclude that reproducible contractile responses with an identifiable nerve-induced component can be obtained from the mouse inferior pharyngeal constrictor. The pharyngeal muscles have contractile characteristics similar to those of the faster diaphragm. The sensitivity to the neuromuscular blocking agent gallamine of the inferior pharyngeal constrictor was in the same concentration range as that of the diaphragm and soleus muscles.

FWA116基因在心衰动物模型心脏血管内皮的表达

建立亚急性和慢性心衰SD大鼠模型，用RNA-RNA原位杂交方法观察新基因FWA116在心脏组织的表达。以重组质粒FWA116／PGEM-T线性cDNA为模板，在T7或SP6RNA聚合酶作用下，体外合成地高辛（DIG）半抗原标记的FWA116cRNA探针。结果表明：与对照组相比，该基因在两种心衰大鼠心脏的中、小动脉内皮组织的mRNA表达均明显增高；与Northern blot及免疫组化的结果相一致，这提示DIG标记cRNA原位杂交方法的敏感和可靠。同时，FWA116基因在心衰缺血缺氧心脏动脉内皮中的转录和翻译水平的高表达，说明该基因可能在心衰的病理过程中起到重要的作用。