Human Dental Pulp Stem Cells Exhibit Osteogenic Differentiation Potential

Abstract

Bone regeneration after trauma, pathologic and surgical procedures is considered a major medical challenge. Due to limitations in using conventional approaches, cell based regenerative strategies may provide an alternative option to address such issues. In the current study, we sought to determine the osteogenic potential of dental pulp stem cells (DPSCs) isolated from impacted 3^rd molars. DPSCs were isolated from human dental pulp tissue (n=6) using explant culture. Growth characteristics of DPSCs were determined using plating efficiency, and the number and time of population doublings. After characterization, DPSCs were induced to differentiate into osteoblasts and were assessed using polymerase chain reactions (PCR) and histological analysis. Results indicated that DPSCs can be isolated from impacted human third molars, and that DPSCs exhibited typical fibroblastic morphology and excellent proliferative potential. In addition, morphological changes, histological analysis and expression of lineage specific genes confirmed osteogenic differentiation of DPSCs. In conclusion, DPSCs isolated from impacted 3rd molars have high proliferative potential and ability to differentiate into osteoblasts.

Keywords: dental pulp; human dental pulp stem cells; impacted tooth; osteoblast; third molars.

Figure 1

OPG, extract tooth and explant culture. A) An OPG showing impacted tooth. B) Extracted tooth in PBS. C) Pieces of pulp. D) MSCs started coming out of small DP pieces at 6-10 days. DP-MSCs at approximately 2 weeks after culture E) Cells formed monolayer after 14-21 days. OPG: orthopentomogram, DP: Dental pulp; MSCs: Mesenchymal stem cells.

Figure 2

DPSC derived colonies and plating efficiency. A) showing colonies (low and high density) derived from DPSCs after 14 days. Colonies were stained with crystal violet dye. B) Low density colony of DPSCs and C) showing high density colony of DPSCs. D) Shows plating efficiency of all samples with different ages (n=6).

Figure 3

Proliferative potential of DPSCs. Passaging of DPSCs A) passage 1 B) passage 3 C) passage7 D) passage 10 E) cumulative population doublings of all six samples with different age groups from p0 to p 10 F) population doubling time of DPSCs was calculated for all six samples from P0- P10 , which was 1.95days ± 0.080, DP-MSCs shows an ideal PDT proving that these cells are easily expendable.

Figure 4

Differentiation potential of DPSCs. A) controlled, B, C) Von kossa staining at day 14 and 21 respectivly, confirming mineral deposition by newly formed osteoblasts D) alizarin red staining at day 21 E) showing positive results of RUNX2 and OCN at day 14 and 21 of osteogenic differentiation through polymerase chain reaction.