间充质干细胞治疗急性骨髓型放射病的实验研究

目的研究骨髓间充质干细胞(MSCs)在治疗急性骨髓型放射病中的作用,并对其机理做初步的探索。方法BALBc雌性小鼠分成MSCs组和照射对照组,MSCs组经5.5Gy60Coγ射线照射,2h内尾静脉输注C57BL6雄性小鼠的MSCs,照射对照组照射后不作处理。观察各组外周血象变化、骨髓细胞凋亡、细胞增殖周期、骨髓病理变化、骨髓造血粒系祖细胞集落(CFUGM)以及基质细胞集落(CFU-F)计数。结果与对照组相比,MSCs组的三系血细胞下降慢,最低值抬高,并且造血恢复更迅速,尤其白细胞、血小板变化更明显。骨髓细胞凋亡率和P53蛋白表达量少于对照组。照后2d,MSCs组G0G1期比值较对照组明显下降(P<0.01),G2M期比值及S期计数较对照组显著升高(P<0.01)。照后4dMSCs组胸骨骨髓增生活跃,对照组增生减低,照后20dMS-Cs组新生造血灶多于对照。CFU-GM、CFUF计数在照后初期、极期、恢复期均高于对照。结论MSCs对急性放射病治疗有良好的治疗作用,其机制可能与MSCs减少细胞凋亡、改善造血微环境、促进干细胞增殖分化有关。     

放射性胸腺损伤小鼠模型的建立

背景：胸腺对于维持机体免疫功能起着重要的作用,在放射性损伤发生时的损伤和修复机制有待于进一步研究,但目前缺乏相应的动物模型。 目的：单纯照射小鼠胸腺以构建放射性胸腺损伤模型。 方法：160只雌性BALB/C小鼠随机分为4组,每组40只,对照组予以假照射;6 Gy照射组给予⁶⁰Co γ射线6 Gy胸腺单次照射,9 Gy照射组给予胸腺单次照射9 Gy,12 Gy照射组给予胸腺单次照射12 Gy。观察各组小鼠照射后1-7 d体质量及进食水量变化,照射后1,7,14,21,28 d检测各组小鼠血象、胸腺指数及胸腺病理变化,并于照射后7 d检测小鼠食管、肺、气管病理组织学变化,照射后14 d检测小鼠外周血T细胞亚群和胸腺T细胞亚群表达。 结果与结论：与对照组相比,照射组小鼠各项指标均发生变化,但6 Gy照射组由于损伤相对较轻,在照后1周内就开始修复;12 Gy照射组出现了放射性食管、气管损伤,而9 Gy组即保留了放射性损伤的特点,也避免了其他脏器损伤带来的干扰,能反映胸腺放射性损伤后的改变。以9 Gy ⁶⁰Co γ射线单次纵膈照射可成功制作小鼠放射性胸腺损伤模型。     

IL-7和EGFP双基因共表达重组腺病毒载体的构建

目的：构建白细胞介素7（IL-7）和增强型绿色荧光蛋白（EGFP）共表达的重组腺病毒载体,为进一步感染干细胞奠定基础。方法：将目的基因IL-7克隆到含有报告基因EGFP的穿梭质粒中,然后再将构建的重组穿梭质粒转移至pAdxsi载体中,构建重组腺病毒载体质粒,继而在H293细胞中扩增,纯化后测定病毒滴度。结果：pShuttle-EGFP-mIL7重组穿梭质粒经酶切鉴定得到0.5kb和5.1kb 2条带;pAdxsi-EGFP-mIL7重组腺病毒载体质粒经酶切鉴定得到14K、11.8K、3.1kb、2.66kb、2.47K、1.45K、0.6K 7条带;TCID50法测定纯化后的病毒滴度为2×10^10pfu/ml。结论：pAdxsi-EGFP-mIL7重组腺病毒载体构建成功。     

骨髓间充质干细胞静脉输注对猕猴细胞免疫功能的影响

 目的　评价猕猴间充质干细胞（MSC）静脉异体输注后对细胞免疫功能的影响。方法　分离培养MSC;不做其他处理,将异体MSC 静脉输注给受者猴,通过定期监测外周血象、混合淋巴细胞反应（MLR）、T细胞亚群来判断MSC输注后受者细胞免疫功能的变化。结果　成功培养了猕猴的MSC。异体MSC 输注后,受者无明显毒性反应、排异表现及血象变化。可以在一定时间内（2周左右）抑制受者T细胞在MLR中的增殖活性,受者猴A2、A3及A4输注MSC 的数量分别为4.0×105／kg、1.0×106／kg、2.0×106／kg,在输注后第14天时,MLR的相对反应值（RR）与输注前比较均明显降低,分别从（46.0±2.6）%、（40.9±2.3）%、（48.3±2.0）%降至（40.4±1.73）%、（33.0±2.1）%、（39.0±1.0）%（F＝10.19,P＝0.023;F＝2.593,P＝0.013;F＝28.431,P＝0.003）,输注后第30天时RR均恢复到输注前水平;统计结果显示,抑制程度（ΔRR）与输注MSC 数量呈正相关（F＝27.413,P＝0.038）。A4是输注MSC 数量最多的受者,输注后第14天开始,外周血CD+3、CD+3 CD+4、CD+3 CD+8细胞的百分比与输注前相比有所降低,在输注后第30天左右恢复至输注前水平。结论　单纯体内输注异体MSC,可以在一定时间内抑制受者T细胞的免疫活性;免疫抑制程度与输注MSC数量呈正相关。MSC 特殊的免疫学特性使其具有深远的临床应用价值。     

改良小鼠骨髓间充质干细胞培养方法及长效荧光标记的可行性

背景：小鼠骨髓间充质干细胞培养不同于人及大鼠,培养扩展难度高,传代后干细胞活性保持时间短;又鉴于干细胞本身特点,使现有干细胞示踪方法作用时间短,这些因素均影响小鼠骨髓间充质干细胞的实验研究。 目的：观察改良小鼠骨髓间充质干细胞分离培养方法及长效荧光标记干细胞的可行性。 设计、时间及地点：观察性实验,于2008-06/12在解放军军事医学科学院完成。 材料：C57BL/6小鼠4~6周龄,体质量20 g,雌雄不拘。 方法：通过贴壁筛选和Percoll分离法,优化干细胞培养液血清和换液方式,培养扩增小鼠骨髓间充质干细胞。参照以往人和猕猴间充质干细胞培养经验,对小鼠间充质干细胞培养血清选择Hyclone的顶级胎牛血清,控制血清为培养液的10%。用LG-DMEM培养液冲出骨髓细胞后,滤去骨渣和小肌肉碎块。然后加在相对密度1.082的percoll分离液上,以1.5×106/cm2浓度接种75 cm2培养瓶。对第2代骨髓间充质干细胞进行长效CM-DiI标记。 主要观察指标：原代及传代小鼠骨髓间充质干细胞形态变化;对第2代小鼠骨髓间充质干细胞表面抗原,CD105,CD44,CD25,CD34进行流式细胞仪检测,评价改良方法获取干细胞纯度;通过成脂成骨分化,鉴定小鼠骨髓间充质干细胞的活性;观察多次传代后荧光细胞强度。 结果：①小鼠骨髓间充质干细胞原代培养在接种48 h后可见贴壁细胞,培养第7天细胞多数伸展呈梭形,也有三角形、多角形和扁平形。3代后形态趋于统一,融合状态时细胞排列呈束状、漩涡状或放射状。②骨髓间充质干细胞特异性抗原高表达CD105,CD44;造血系抗原低表达CD34和CD45。③骨髓间充质干细胞向成骨分化过程中,纺锤形的突起逐渐消失,胞体增大,培养10 d后,部分细胞呈聚集生长,随细胞生长密度的增长形成多层的结节结构。在脂肪诱导体系中,可见细胞由成纤维样逐渐缩短,9 d后胞浆中出现脂肪滴,油红O染色可见红色的脂肪颗粒。④首次标记,荧光显微镜观察可见长效CM-DiI标记在细胞膜发橙色光,标记率在80%以上。流式细胞仪检测CM-DiI细胞标记率可到47%以上,第4代培养细胞仍可见较多标记细胞。 结论：改良方法早期第2代就可获得高浓度干细胞,同时长效CM-DiI标记方法稳定,标记率高,可作体内细胞示踪。     

骨髓间充质干细胞防治多脏器衰竭

Objective The patients with lethal irradiation after sucessful hematopoietic stem cells transplan-tation had blood recovery, but did not avoid to died of multiple organ failure(MOF). To overcome the block, the article investigated mechanisms of mesenchymal stem cells (MSCs) protecting lethal radiated mice from multiple organ failure after haploid bone marrow cells transplantation. Method BALB/c mice irradiated with 8Gy60COγ-rays were randomly divided into two groups: MSCs group, infused MSCs labeled with cm-DiI and bone marrow monocytes of CB6F1 mice; Control group, only infused bone marrow monocytes; normal group, mice were infused cm-DiI marked MSCs without irradiation. The distribution of MSCs and the serous densities of Il-2, Il-10 and TNF-α in the recipients were observed after transplantation. Results MSCs collected in the bone marrow and the intes-tine in normal group at 15 d,in MSCs group MSCs enriched the different organs at 3,15 and 30 d. MSCs regulated down the secretion of IL-2 and TNF-α,and up the IL-10 density. Conclusions MSCs protected mice from multiple organ failure through above effects and may be open a new treatment strategy on acute radiation syndrome by stem cells.     

骨髓间充质干细胞防治多脏器衰竭

Objective The patients with lethal irradiation after sucessful hematopoietic stem cells transplan-tation had blood recovery, but did not avoid to died of multiple organ failure(MOF). To overcome the block, the article investigated mechanisms of mesenchymal stem cells (MSCs) protecting lethal radiated mice from multiple organ failure after haploid bone marrow cells transplantation. Method BALB/c mice irradiated with 8Gy60COγ-rays were randomly divided into two groups: MSCs group, infused MSCs labeled with cm-DiI and bone marrow monocytes of CB6F1 mice; Control group, only infused bone marrow monocytes; normal group, mice were infused cm-DiI marked MSCs without irradiation. The distribution of MSCs and the serous densities of Il-2, Il-10 and TNF-α in the recipients were observed after transplantation. Results MSCs collected in the bone marrow and the intes-tine in normal group at 15 d,in MSCs group MSCs enriched the different organs at 3,15 and 30 d. MSCs regulated down the secretion of IL-2 and TNF-α,and up the IL-10 density. Conclusions MSCs protected mice from multiple organ failure through above effects and may be open a new treatment strategy on acute radiation syndrome by stem cells.     

骨髓间充质干细胞防治多脏器衰竭

Objective The patients with lethal irradiation after sucessful hematopoietic stem cells transplan-tation had blood recovery, but did not avoid to died of multiple organ failure(MOF). To overcome the block, the article investigated mechanisms of mesenchymal stem cells (MSCs) protecting lethal radiated mice from multiple organ failure after haploid bone marrow cells transplantation. Method BALB/c mice irradiated with 8Gy60COγ-rays were randomly divided into two groups: MSCs group, infused MSCs labeled with cm-DiI and bone marrow monocytes of CB6F1 mice; Control group, only infused bone marrow monocytes; normal group, mice were infused cm-DiI marked MSCs without irradiation. The distribution of MSCs and the serous densities of Il-2, Il-10 and TNF-α in the recipients were observed after transplantation. Results MSCs collected in the bone marrow and the intes-tine in normal group at 15 d,in MSCs group MSCs enriched the different organs at 3,15 and 30 d. MSCs regulated down the secretion of IL-2 and TNF-α,and up the IL-10 density. Conclusions MSCs protected mice from multiple organ failure through above effects and may be open a new treatment strategy on acute radiation syndrome by stem cells.     

骨髓间充质干细胞防治多脏器衰竭

Objective The patients with lethal irradiation after sucessful hematopoietic stem cells transplan-tation had blood recovery, but did not avoid to died of multiple organ failure(MOF). To overcome the block, the article investigated mechanisms of mesenchymal stem cells (MSCs) protecting lethal radiated mice from multiple organ failure after haploid bone marrow cells transplantation. Method BALB/c mice irradiated with 8Gy60COγ-rays were randomly divided into two groups: MSCs group, infused MSCs labeled with cm-DiI and bone marrow monocytes of CB6F1 mice; Control group, only infused bone marrow monocytes; normal group, mice were infused cm-DiI marked MSCs without irradiation. The distribution of MSCs and the serous densities of Il-2, Il-10 and TNF-α in the recipients were observed after transplantation. Results MSCs collected in the bone marrow and the intes-tine in normal group at 15 d,in MSCs group MSCs enriched the different organs at 3,15 and 30 d. MSCs regulated down the secretion of IL-2 and TNF-α,and up the IL-10 density. Conclusions MSCs protected mice from multiple organ failure through above effects and may be open a new treatment strategy on acute radiation syndrome by stem cells.     

猕猴非清髓单倍相合造血干细胞移植模型的建立

为了研究用非清髓预处理是否能建立猕猴单倍相合造血干细胞移植模型，采用健康、单倍相合的亲代猕猴为供者，子代为受者。受体用氟达拉滨＋环磷酰胺＋全身照射＋兔抗人胸腺细胞球蛋白作非清髓性预处理；用环胞菌素A、霉酚酸酯、鼠抗人CD25单克隆抗体作为移植物抗宿主病（GVHD）预防方案；第0天输注供者动员后的外周血造血干细胞；定期监测造血恢复、造血嵌合水平和GVHD发生等情况。结果表明：4例猕猴用非清髓性预处理后，移植后8天内造血均能恢复，早期均有供者造血干细胞植入；例3、例4植入成功，在移植后12、14天出现Ⅱ-Ⅲ度GVHD；例1在移植后7天低比例供者植入，最后出现移植排斥；例2在移植后7天供者成分占50％，后因肾衰早期死亡。结论：用非清髓性预处理可以跨越单倍相合猕猴的MHC屏障，成功建立了单倍相合造血干细胞移植的模型。为进一步买验研究奠定了基础。