人牙周韧带细胞和牙髓细胞表型特征的比较

目的研究人牙周韧带细胞（PDLCs）和牙髓细胞（DPCs）表型特征以及体外传代对其表型特征的影响，为选择适宜的表面标记分选生物性状同源性的细胞亚群提供依据。方法采用酶消化法体外培养PDLCs和DPCs，免疫组化检测和流式细胞仪分析细胞表面标记的表达。结果PDLCs和DPCs的STRO-1和CD146免疫组化染色阳性。流式细胞仪分析显示：获得的第1代PDLCs和DPCs表达间充质干细胞表面标记STRO-1、CD146、CD29、CD44和CD106，基本不表达CD34。PDLCs的STRO-1、CD29和CD44阳性表达百分比与DPCs间的差异无统计学意义（P>0.05），PDLCs的CD106阳性表达百分比高于DPCs，CD146阳性表达百分比低于DPCs，且差异有统计学意义（P<0.001）。PDLCs和DPCs表达STRO-1和CD146的阳性表达百分比随传代而逐渐减低。结论PDLCs表面抗原表达与DPCs相似，而且其中成体干细胞的成分随传代逐渐减少。

The surface antigen expression of periodontal ligament cells and dental pulp cells in vitro

Objective To investigate the expression of surface antigen of human periodontal ligament cells （PDLCs） and dental pulp cells（DPCs） and the impact of ex vivo expansion to the expression of surface antigen. To provide basis of proper surface antigen for further selection of homogenous stem cell subpopulation from PDLCs and PCs. Methods PDLCs and DPCs were isolated and cultured by collagenase type I and dispase. The expression of surface antigen was analyzed by immunohistochemistry and flow cytometry. Results Positive expression of STRO-1 and CD146 were observed in PDLCs and DPCs by immunocytochemistry. Similar to DPCs, PDLCs expressed mesenchymal stem cell markers STRO-1, CD146, CD29, CD44 and CD106, and displayed negative expression for CD34 at passage 1 by flow cytometry. There were no significant difference of STRO-1, CD29 and CD44 expression level between PDLCs and DPCs（P>0.05）. PDLCs expressed significantly higher level of CD106 and significantly lower level of CD146 than DPCs（P<0.001）. The proportion of STRO-1 and CD146 positive cells decreased steadily with passages in PDLCs and DPCs. Conclusion PDLCs have some similar surface antigen as DPCs, and the stem cells properties of PDLCs and DPCs decreased steadily with passages.