Dentin-pulp complex regeneration by porcine dental papilla cells (pDPCs)

Dental papilla is the precursor of dentin-pulp complex during tooth development, and it is thought to be the most suitable cell source for regeneration of dentin-pulp complex. Usually, researchers use rat or mouse as experimental model in tooth regeneration, and pig is relatively less to be used. Objective: To regenerate dentin-pulp complex by porcine dental papilla cells cultured in vitro. Methods: Porcine dental papilla cells(pDPCs) were in vitro cultured in the medium of DMEM/F12 containing 10%FBS by enzyme digestion method. H&E staining, ALP staining, RT-PCR and histoimmunochemistry methods were used to describe the cell's biological characteristics and identify the dentinogenic potential of pDPCs. Then the second passage cells were collected and seeded at the density of 1×106cells/cm3 onto the scaffold of tricalcium phosphate (TCP), and transplanted subcutaneously into athymic mice. The implants were harvested after 15W and stained witn H&E, Goldner's Trichrome. Results: The morphology of pDPCs looks like fibroblasts, and seemed to have more prominencies. Compared with bone marrow stromal cells (BMSCs), pDPCs cultured in vitro have more granules in the plasma. Positive ALP staining indicated that the pDPCs have the potential to form calcified tissues. DSPP expression was detected in pDPCs cultured in vitro by RT-PCR, and DSP was still positive expressed in passage 6. The results of the implants showed that dentin-pulp like complex was formed according to the 3-dimensional structure of scaffold, but the dentin tubules were not so typical than natural dentin structure. Conclusions: Porcine DPCs are resemble to BMSCs in biological characteristics, and have the dentingenic potential to form dentin-pulp complex. We are looking forward to regenerate whole tooth by using pDPCs and odontogenic epithelium cultured in vitro.