dNCPs can Stimulate Dental Follicle Cells Towards Cementoblasts Differentiation

Objectives:To explore the effects of dentin or dentin matrix on dental follicle cells at the onset of cementogenesis. Methods: Dental follicle cells were isolated from tooth germs of SD rats. Dentin non-collagenous proteins(dNCPs) were used as the stimulator to influence dental follicle cells. Morphological observation including SEM and TEM, MTT test, cell cycle analysis, ALP activity, mineralized nodule formation and immunocytochemisty as well as RT-PCR, were conducted to investigate the in vitro changes of dental follicle cells after induction. Cell pellet loaded in carrier of developing dentin was adopted as the transplantation model of in vivo study. Results: After dNCPs induction, DF cells presented a significant morphological change from fibroblast-like shape to mineral-forming cells, as well as decreased proliferation , accelerated ALP activity and matrix mineralization. The expression of mineralization-associated proteins and genes were up-regulated by induction, except negative expression of odontoblast specific markers. After incubated for 4 weeks in the renal capsules of rat hosts, pellets of induced DF cells formed large amount of mineralized tissue within the developing dentin carriers, which is different from newly formed osteodentin secreted by DPSCs. DSP-immunochemistry staining also excluded the possibility of producing dentin by the induced DF cells. Conclusion: dNCPs can activate DF cells toward the cementoblasts phenotype. This study provides new insights into the mechanism of cementogenesis .