人脐血间充质干细胞体外分离培养条件的优化及其鉴定

背景:相对于骨髓间充质干细胞来说,脐血间充质干细胞是一种较为理想的新的组织工程种子细胞来源,但其培养成功率较低.目的:通过对培养基的选择、离心速度及时间、接种密度、生长因子的选择、首次换液时间等条件进行优化,拟建立一种稳定可靠的人脐血间充质干细胞的体外分离培养方法.设计、时间及地点:细胞学体外观察,于2008-01/10在白求恩国际和平医院输血科完成.材料:健康足月剖宫产新生儿脐带血20份,由白求恩国际和平医院干细胞中心提供,产妇及其家属均知情同意.方法:无菌条件下采集脐血,采用密度梯度离心法(1500 r/min离心15 min)结合直接贴壁法体外分离脐血间充质干细胞,加入含体积分数为10%人脐带血血清、5 μg,L GM-CSF、15 μg/L白细胞介素3的DMEM/F12培养基,调整细胞密度为1×1010L-1接种于人脐带血血清包被过的塑料培养瓶中,置于37℃、体积分数为5%的CO2饱和湿度环境下培养,3 d后首次换液,去除未贴壁细胞,以后每隔24 h换液1次.当培养瓶中的细胞生长到80%融合时,胰酶-EDTA混合液消化传代.主要观察指标:倒置相差显微镜下观察细胞形态变化,流式细胞仪检测细胞免疫表型.结果:24 h后可见有少量细胞贴壁,48 h后贴壁细胞增多,并出现少量单极梭形细胞,7d后可见细胞形成集落,培养两三周形成平行排列、辐射状或漩涡状细胞界限不清楚的成纤维样细胞,且80%～90%呈现融合.第2代细胞接种后12 h开始贴壁,10 d即可达80%～90%融合.流式细胞仪分析显示,此类细胞稳定地表达相关抗原标记CD29及CD44,但不表达造血细胞系表面标记CD34.结论:实验在体外改良培养条件下成功分离出人脐血间充质干细胞,培养周期较短,细胞纯度较高,贴壁细胞稳定表达间充质干细胞表面相关抗原.

Optimization and identification of in vitro isolation and culture condition of human umbilical cord blood mesenchymal stem cells

BACKGROUND: Compared with the bone marrow mesenchymal stem cells, umbilical cord blood mesenchymal stem cells (UCB-MSCs) is an ideal source of tissue engineered seed cells, but the culture success rate is low.OBJECTIVE: To explore establish a stable reliable method to isolate and culture UCB-MSCs by optimizing medium choice,centrifugation speed and time, incubation density, choice of growth factor, first time of medium change.DESIGN, TIME AND SETTING: The cytological in vitro study was performed at the Department of Blood Transfusion, Bethune International Peace Hospital of Chinese PLA from January to October 2008.MATERIALS: A total of 20 samples of neonatal UCB by full-term uterine-incision delivery were supplied by Stem Cell Center,Bethune International Peace Hospital of Chinese PLA. Parturient and their family member signed the informed consent.METHODS: Under sterile conditions, UCB-MSCs were isolated by combination of density gradient centrifugation (1 500 r/min, totally 15 minutes) and different adherent time method. UCB-MSCs were incubated in DMEM/F12 medium, supplemented with 10% human UCB serum, 5 μg/L granulocyte-macrophage colony-stimulating factor (GM-CSF), 15 pg/L interleukin-3. MSCs at 1 ×1010/L were incubated in plastic flask coated with human UCB serum at 37℃ and 5% CO2 saturated humidity. The medium was changed following 3 days of culture. Non-adhered cells were removed. Subsequently, the medium was changed once every other 24 hours. When 80% confluence, UCB-MSCs were digested by the mixture of pancreatin-athylenediamine tetraacatic acid.MAIN OUTCOME MEASURES: Morphological changes of UCB-MSCs were observed by inverted phase contrast microscopy. Cell immunophenotypes were determined by flow cytometry.RESULTS: A small quantity of adherent round cells were determined after 24 hours, and adherent cells became more at 48 hours,with a few monopole spindle cells. Cell colonies were detected at day 7. Fibroblast-like cells arranged parallelly, presented whirlpool-shape and unclear boundary, with 80% 80% confluence 2-3 weeks following culture. At the second passage, these calls adhered at hour 12, and reached 80% 90% confluence at day 10. Flow cytometry showed that these calls were positive for CD29 and CD44, but negative for hematopoietic lineage marker CD34.CONCLUSION: MSCs can be successfully isolated from human UCB by using this modified method in vitro, with short culture cycle and high cell purification. Adherent cells have the same immunophenotype as bone marrow mesenchymal stem cells.