ABSTRACT
As one type of adult stem cells (ASCs), human dental pulp stem cells (HDPSCs) have several properties, including high proliferation rate, selfrenewal capability, and multilineage differentiation. However, the apoptotic mechanism underlying the development of dental pulp cells remains unclear. In the present study, a significant increase of apoptosis was observed in HDPSCs from the deciduous teeth compared with that from adult permanent teeth. In addition, the occurrence of cytochrome c expression and mitochondrialmediated apoptosis pathway activity in HDPSCs were confirmed by quantitative polymerase chain reaction, and western blotting. Although caspase8 and caspase9 showed higher expression in deciduous teeth than in adult permanent teeth, only the knockdown of caspase9 via RNA interference in HDPSC cells exhibited a significant reduction in apoptosis, and caspase3 expression and activity. All these results revealed that caspase9 and activated caspase3 predominantly regulates cell apoptosis in HDPSCs from deciduous teeth.