Effect Of DEMPs On Proliferation And Differentiation Of SHED In Vitro

Backgraunds:Teeth as the most organs close relation with human life, once missing will not be able to regenerate, which greatly influence psychological health and quality of life of people. Study of tooth regeneration has become a hot research in the field of stomatology. In 2000, scholars in human dental pulp tissue successfully isolated with cloning ability and high proliferation and differentiation potential of mesenchymal cells, named for dental pulp stem cells. This discovery has brought hope to achieve the tooth regeneration.Mature tooth is composed of enamel, dentin, pulp and cementum. Enamel is the first line of defense against outside stimulation. Dentin as the main support structure of teeth, composed of dentin tubule and extracellular matrix, is the main line against stimulation. Dental pulp as the main part of the cell composition in teeth provides nutrition for the dentin. As the teeth have been relatively strong stimulited, the corresponding part of the dentin cells will be destroyed and around the dental pulp stem cell will die. In such circumstances, dentin extracellular matrix protein components will release, stem cells within the pulp can be recruited to the site of injury and induced to differentiate into odontoblast-like cells leading to tertiary dentine synthesis and bridge formation at sites of pulpal exposure. It is clear that dentine matrix contains a broad spectrum of bioactive molecules, which if released can act to stimulate and modulate many of the cellular events taking place during regeneration of dentine–pulp.Dentin as the mineralized extracellular matrix, contains many biological active molecules, these extracellular matrix molecules play an important role in tooth regeneration. Dentin extracellular matrix comprises collagenous and non-collagenous proteins(NCPs). This NCP component is known to contain a significant number of well characterised bioactive regulatory molecules such as dentine sialoprotein(DSP), dentine phosphoprotein(DPP), bone sialoprotein(BSP), dentine matrix protein-1(DMP-1) and osteopontin. Mutations in DSPP result in the genetic diseases dentinogenesis imperfecta and dentine dysplasia. DMP-1 is expressed in differentiating odontoblasts, and is essential for mineralisation and maturation of predentine to dentine during dentinogenesis. Osteopontin(OPN) is expressed not only in dentine, but also in various cells and tissues, including bone, and data indicate that this molecule has an inhibitory effect on hydroxyapatite formation and growth. Researches on dentin extracellular matrix proteins for stem cell mostly focus on a single protein, the influence of mixed protein in the field of stem cell function is less reported.Objective:To investigate the effect of DEMPs on proliferation and differentiation of SHED in vitro with an aim to provide theoretical basis for DEMPs in the application of tooth reparation and regeneration. Methods: The stem cells were collected from human exfoliated deciduous teeth by enzyme digestion and tissue ex-plant method. We assess the cells multi-differentiation potentials by inducement. Extracted healthy teeth from cattle, then prepared dentine matrix 4mol/L guanidine hydrochloride and 0.5mol/L EDTA extracts. The effect of DEMPs on the proliferation activity of SHED was evaluated by MTT method and the effect of DEMPs on the activity of ALP was also examined. DSPP and DMP-1 m RNA in effected cells increased. Results: DEMPs could stimulate the proliferation of SHED three and five days later, and increase the activity of ALP five and seven days later. Real-time PCR demonstrated m RNA expression of DSPP and DMP-1 in SHED induced by DEMPs.Conclusion: DEMPs can promote the proliferation and the odontogenic differentiation of SHED.