Retinoic and ascorbic acids induce osteoblast differentiation from human dental pulp mesenchymal stem cells

Area of Science:

• Stem cell biology
• Regenerative medicine
• Biomaterials science

Background:

• Retinoic acid (RA) and ascorbic acid (AA) are known to stimulate osteoblastic differentiation.
• The specific roles of RA and AA in the osteogenic differentiation of human dental pulp stem cells (hDPSCs) are not fully understood.
• Understanding these roles is crucial for developing new strategies in bone tissue engineering and regenerative dentistry.

Purpose of the Study:

• To investigate the effects of retinoic acid (RA) and ascorbic acid (AA) on osteogenic differentiation of hDPSCs.
• To evaluate the impact of RA and AA, alone and in combination, on hDPSCs' morphology, proliferation, and osteogenic markers.

Main Methods:

• Human dental pulp stem cells (hDPSCs) were cultured and treated with varying concentrations of RA and AA, individually and combined.
• Cell proliferation was assessed over 12 days.
• Osteogenic differentiation was evaluated using alizarin red staining for calcification, alkaline phosphatase activity assays, and RUNX2 gene expression analysis.

Main Results:

• RA and combined RA+AA treatments significantly reduced hDPSCs proliferation by 26% and 30%, respectively.
• AA alone reduced cell proliferation by 12%.
• All treatments (RA, AA, RA+AA) induced morphological changes, increased calcified nodule formation, elevated alkaline phosphatase activity, and upregulated RUNX2 gene expression, indicating osteogenic differentiation, with RA showing a predominant effect in combination with AA.

Conclusions:

• Retinoic acid (RA) and ascorbic acid (AA) promote osteogenic differentiation of hDPSCs, characterized by reduced proliferation, morphological changes, and increased RUNX2 expression.
• Ascorbic acid (AA) alone induced morphological changes and early calcified nodule formation.
• Combined treatment of RA and AA demonstrated a synergistic effect, leading to more pronounced osteogenic differentiation of hDPSCs.