人牙髓干细胞的高效扩增及其对分化潜能的影响

目的检测不同接种密度对人牙髓干细胞（Dental pulp stem cells，DPSCs）增殖能力和分化潜能的影响．建立其高效扩增方法。方法不同密度接种培养DPSCs，计算细胞产量、倍增次数．观察细胞形态、检查克隆形成率和钙结节形成能力。结果低密度培养的乳牙牙髓干细胞（Stem cells from human exfoliated deciduous teeth，SHED）始终保持较高增殖、克隆形成率；而低密度DPSCs只在前3代保持与常规密度相似的增殖、克隆形成效率，3代以后其增殖和分化能力明显下降。低密度培养条件下DPSCs的矿化能力与常规密度的没有明显差别。结论1．5～3cells／cm^2低密度接种培养DPSCs有利于细胞快速扩增，扩增后的细胞保持较高的增殖和分化潜能。SHED的增殖能力、克隆形成效率和钙结节形成能力均优于DPSCs。

Maximal Expansion of Stem Cell from Human Dental Pulps and Evaluation of Their Differentiation Capability

Objective The effect of plating density on human dental pulp stem cell expansion and their differentiation capability were examined in order to establish optional plating density for maximal expansion. Methods Cells were plated at different density; cell yield and population doubling were calculated; cell morphology, colony forming efficiency and mineralized nodule formation were further examined after culture. Results SHED retained high proliferating rate, normal cell morphology, and higher CFE during 10 pass expansion when plating at low density （1.5 cells/cm^2 or 3 cells/cm^2）. While DPSCs displayed an decreased proliferating rate, abnormal cell morphology, and lower CFE after 3 pass when plating at low density. Conclusion Plating at low density benefits rapid expansion of DPSCs and SHEDs ex vivo. The optimal density for maximal expansion was 1.5-3.0 cells/cm^2. SHED had a better expansion and differentiation capacity than that of DPSCs.