Investigation of the Effect of a Time Delay on the Characteristics and Survival of Dental Pulp Stem Cells from Extracted Teeth

Abstract Objectives This study investigates the post-extraction storage period of human dental pulp stem cells (hDPSCs) for stem cell banking by investigating the viability, function, mineralization, and gene expression of hDPSCs isolated from extracted teeth after 1 hr, 6 hrs and 24 hrs post-tooth extraction. Design hDPSCs were extracted from the pulp of impacted third molar teeth after 1 hr, 6 hrs, and 24 hrs after extraction. The mesenchymal stem cell (MSCs) properties of three groups of cells were analyzed using flow cytometry. Cell morphology and proliferation were analyzed using a light microscope and an MTT assay. The viability, function, mineralization, and gene expression of hDPSCs of 1 hr, 6 hrs, and 24 hrs groups were also assessed. Results The delayed harvesting of hDPSCs for 1, 6 or 24 hrs caused a 31% reduction in mineral nodule formation and a reduction in the gene expression of osteocalcin (OCN) and vascular endothelial growth factor-alpha (VEGFA). However, the 1, 6 or 24 hrs, time delay had little effect on MTT cell proliferation, cell viability or morphology. The delayed of harvesting of hDPSCs for 1, 6 or 24 hrs also had little effect on the expression of positive (CD44, CD106, CD90) or negative markers (CD45 and CD11b). Conclusions Our results suggest that a 24 hrs delay in harvesting hDPSCs from extracted teeth can reduce their mineralization and gene activity but does not markedly reduce survival. Quicker hDPSCs harvesting is likely to yield more useful hDPSCs for experimentation and clinical treatments.