中文摘要：

目的探讨人牙周膜干细胞（PDLSCs）向脂肪细胞定向分化潜能,分析其分化过程中形态与功能变化。方法免疫磁珠法分离人PDLSCs,用成脂诱导液连续诱导21d,通过倒置显微镜、透射电镜、流式细胞仪、RT-PCR、Westernblot及免疫荧光方法观察诱导细胞形态、结构变化,分析其表面脂肪细胞特异性标志——低密度脂蛋白（LPL）和过氧化物酶体增殖物受体γ（PPAR-γ）的基因及蛋白表达时相及表达量,油红O染色检测脂滴分泌情况。结果诱导21d,诱导细胞呈脂肪细胞样圆形细胞,超微结构观察可见胞浆中大量脂肪细胞特征性脂滴。流式分析结果显示,有96.54%的PDLSCs向脂肪细胞分化。诱导细胞表达脂肪细胞特异性表面标志LPLmRNA和PPAR-γmRNA及PPAR-γ蛋白,且随诱导时间延长PPAR-γ蛋白表达量增加。诱导细胞产生油红O阳性染色的脂滴。结论人PDLSCs在适当条件下可定向分化为脂肪细胞样细胞,并具有脂肪细胞形态、结构和功能特点,具有可塑性。

英文摘要：

Objective To explore the capability of human periodontal ligament stem cells（PDLSCs） differentiating into adipose cells in vitro and to determine their changes in cell morphology, structure and function during differentiation. Methods PDLSCs isolated by magnetic-activated cell selection were treated continuously with adipogenic medium for 21 d. Then the cell morphology, ultrastructure, adipose specific markers of low density lipoprotein（LPL） and peroxisome proliferator activated receptor -γ（PPAR -γ） were analyzed by inverted contrast microscope, transmission electron microscope（TEM）, flow cytometry, immunofluorescence, RT-PCR and Western blot, respectively. These adipose-like cells were also identified by oil red O staining to determine the formation of lipid droplet, and the non-induced cells were used as control. Results After continuous induction, the treated cells differentiated into adipose-like cells with round shape, and large amount of lipid drop in cytoplasm. 96.54% of the PDLSCs were found to differentiate into adipose cells as showed by flow cytometry, the specific markers of LPL mRNA and PPAR-γ mRNA, and oil red O staining, respectively. Further, PPAR-γ protein was detected in the induced cells in a timedependent manner. Conclusion Human PDLSCs have the potential of differentiating into adipose cells under appropriate condition, and the differentiated cells exhibited characteristics of adipose cells both from cell morphology and from their functions.