OBJECTIVETo 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.

METHODSPDLSCs 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-gamma (PPAR-gamma) were analyzed by inverted contrast microscope, trans mission 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.

RESULTSAfter 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-gamma mRNA, and oil red O staining, respectively. Further, PPAR-gamma protein was detected in the induced cells in a time-dependent manner.

CONCLUSIONHuman 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.