Experiment on inducing periodontal ligament stem cell to differentiate into osteoblasts in vitro

Objective:To explore the capability of human periodontal ligament stem cells(PDLSCs) differentiating into osteoblasts in vitro and to determine their changes in cell morphology and function during differentiation at cellular level,molecular level and genetic level,respectively.Methods: PDLSCs isolated by magnetic-activated cell selection were treated continuously with mineralization solution for 21d.Then cell morphology,osteoblast related proteins and genes markers were analyzed by inverted contrast microscope,immunocytochemical staining,Western blot and RT-PCR,respectively.The ALPase activity was detected at day 7 and day 14 and alizarin red staining was also performed at day 21,the non-induced cell was used as a control.Results:The induced cells differentiated into osteoblast-like cells with polygon in shape after induction for 21 days.Compared with the control group,the ALPase activity of the cells in induced group were significantly higher at day 7 and day 14 and was positively expressed osteogenesis related genes of cement attachment protein(CAP),osteocalcin(OCN),osteopontin(OPN) and Collengen Ⅰ(Col I)mRNA.Moreover,the induced cell positively expressed bone sialoprotein(BSP) and Col I,protein markers of bone cell.In addition,only the induced cell could form mineralized nodes as showed by alizarin red staining.Conclusion:Human PDLSCs have the potential of differentiation into osteoblasts under specific culture condition,and the differentiated cells exhibited characteristics of osteoblast cells both in cell morphology and in cell functions.This study suggests that PDLSCs can be used as a potent seed cell for stem cell-based periodontal and peri-implant bone tissue engineering.