摘要目的 观察体外长期培养人脐带间充质干细胞的生物活性变化特点及评估其安全性.方法 在体外环境中对人脐带来源的间充质干细胞进行了长期的标准化培养,并延长了培养时间,对细胞的表面标记、端粒酶活性、细胞周期、凋亡率、核型及裸鼠成瘤性进行分析.结果 常规体外培养下,间充质干细胞的表面标记持续稳定.端粒酶分析表明随着传代次数的增加,细胞的端粒酶活性表达逐渐降低,细胞周期正常未出现异常凋亡或癌变.核型分析表明细胞增殖过程中细胞核型无异常变化.裸鼠成瘤性实验表明细胞无成瘤性风险.结论 间充质于细胞在体外标准化培养至第15代,细胞分化能力相对减弱.25代以后生长缓慢细胞生物学特征.培养到第30代,表型及基因型无明显变化,未发生恶性转变.

abstractsObjective To determine the alteration in biological features and safety profile of human umbilical cord- derived mesenchymal stem cells (hUC- MSCs) subjected to long- term culture in vitro.Methods A long-term standardized in vitro culture of hUC-MSCs was completed via prolonging the incubation period for analyses on cell surface markers,telomerase activity,cell cycle,incidence of apoptosis,karyotype,and tumorigenicity of nude mice.Results Standardized in vitro culture of hUC-MSCs resulted in stable expression of surface markers.This was associated with tapering,but not markedly increased,telomerase activity despite passages,as suggested by telomerase assessment.In line with absence of apoptotic anomaly or tumorigenesis in cell cycles,the inconsiderable variation in karyotype during cell proliferation did not yield potential risk of tumorigenicity in nude mice.Conclusion The hUC-MSCs cultured in vitro are associated with restrained differentiation capacity at the 15th passage,diminished proliferation potency at the 25th passage and absence of malignant transformation at the 30th passage,as indicated by insignificant alteration in phenotypes and genotypes.