摘要： 目的：研究人脱落乳牙牙源髓干细胞（SHED）在体外长时期扩增，培养至20代后生物学特性的改变，探讨长时间扩增培养对SHED特性的影响。方法：从健康儿童脱落的乳牙中分离牙髓干细胞，在常规条件下扩增培养至第20代，比较第4代、第20代SHED，在细胞形态、增殖速率、多向分化、细胞凋亡等方面的差异。结果：与第4代相比，第20代细胞增殖速率减慢，成脂、成骨分化能力减弱，凋亡细胞增多，但仍能保持干细胞特有的免疫表型，高表达CD73、CD90、CD105，低表达CD34、CD11b、CD19、CD45和 HLA-DR。结论：随着体外扩增至20代，SHED虽能维持干细胞特有的免疫表型，但其生物学特性发生改变，已成为衰老细胞，不再适用于组织工程及干细胞治疗。

关键词: 脱落乳牙干细胞, 体外扩增培养, 生物学特性,  细胞衰老

Abstract: Objective: To investigate the alteration of the biological characteristics    of stem cells derived from human exfoliated deciduous teeth (SHED) during long-term continuous subculture to passage 20 in vitro, and reveal the influence on features of SHED. Methods: SHED were isolated from deciduous teeth of healthy children in mixed dentition stage and subculture to passage 20 under the standard condition. We compared the the cell morphology, proliferation rate, multi-lineage differentiation potential, apoptosis of SHED at passage 4(P4) and passage 20(P20) respectively. Results: SHED exhibited changes in cell morphology, decreased proliferation capacity, attenuated differentiation potential, augmented SA-β-Gal positive cells and increased apoptosis at P20 in comparison with P4, however, they still maintained specific immunophenotypes, highly positive for CD73, CD90, CD105, negative for CD34, CD11b, CD19, CD45 and HLA-DR. Conclusion: SHED underwent senescence and their characteristics changed after serially expanded to P20 even they are able to maintain special immunophenotypes. Therefore, long-term cultivated SHED are not suitable for tissue engineering and stem cell therapy.  

Key words: SHED, long-term expansion in vitro, biological characteristics, cell senescence

中图分类号: 

• R788