Effect of Calcitriol on Differentiation of Periodontal Ligament Stem Cells to Osteoblasts

Background: Periodontium may be able to respond to injuries by regeneration via the function of stem cells. Objectives: This study sought to assess the differentiation of human periodontal ligament stem cells (PDLSCs) into osteoblasts in standard osteogenic medium and in a medium supplemented with 1,25-dihydroxyvitamin D3 (calcitriol). Materials and Methods: In this experimental study, PDLSCs were isolated under sterile conditions by scraping the periodontal ligament tissues attached to the middle third of the root surface of extracted teeth, which were obtained from patients who were candidates for orthodontics therapy in the dental faculty at Hamadan University. The collected cells were cultured on four culture plates for 24 hours. Group 1 contained a basic medium (α-MEM, containing 10% fetal bovine serum (FBS), 5 mM β-glycerophosphate, and 50 µg/mL l-ascorbic acid), supplemented with 10 - 8 M dexamethasone. Group 2 contained a basic medium supplemented with vitamin D3. Group 3 contained a basic medium supplemented with vitamin D3 and dexamethasone, Group4 contained negative control cultures. Alizarin red staining (ARS), alkaline phosphatase (ALP) activity, and calcium content (CC) tests were performed to evaluate osteogenic differentiation of third passage cells in the developing adherent layer. Results: Quantitative analysis of ARS demonstrated that mineralized nodule formation was highest in the group supplemented with calcitriol and dexamethasone (P < 0.001). Results of the ALP test on day 28 demonstrated the highest ALP activity in the group supplemented with calcitriol (P < 0.001). The amount of CC was lowest in the control group at all-time points, and was highest in the group supplemented with both calcitriol and dexamethasone on day 28 (P < 0.001). Conclusions: The combination of calcitriol with dexamethasone, ascorbic acid, and beta-glycerophosphate (that is, the osteogenic medium) may be beneficial for differentiation of PDLSCs into osteoblasts.