Eldecalcitol enhances osteo/odontogenic differentiation and mineralized matrix formation via redox modulation in human dental pulp stem cells.

This study investigated the effects of eldecalcitol (ELD), a synthetic analog of vitamin D3, with immunomodulatory and osteogenic modulatory properties, on the biological behavior of human dental pulp stem cells (hDPSCs) in vitro. Specifically, this study aimed to evaluate the influence of ELD on cell viability, oxidative stress responses, migratory capacity, osteo/odontogenic differentiation, and mineralization potential, with particular attention to elucidating the interplay between redox modulation and the regenerative properties of hDPSCs. hDPSCs were treated with different concentrations of ELD and evaluated at multiple time points. Cell viability was evaluated using the MTT assay, while apoptosis and intracellular reactive oxygen species (ROS) production were analyzed by flow cytometry using Annexin V/7-AAD and CM-H2DCFDA staining, respectively. Cell migration was assessed through wound-healing assays, and cytoskeletal organization was examined by F-actin phalloidin staining. Osteo/odontogenic differentiation was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) by measuring the expression levels of alkaline phosphatase (ALP), collagen type I alpha 1 chain (COL1A1), osteonectin (ON), and bone sialoprotein (BSP). Mineralized matrix formation was assessed by Alizarin Red S staining. Statistical analyses were performed using ANOVA followed by appropriate post hoc tests (p < 0.05). ELD exhibited dose-dependent effects on hDPSC behaviour. Lower concentrations (10⁻5, 10-6 and 10⁻7 M) preserved cell viability, maintained redox balance, enhanced migratory capacity, and promoted a well-organized cytoskeletal architecture. By contrast, higher concentrations (10⁻⁴ M) increased ROS production and apoptosis, ultimately compromising cellular performance. At the transcriptional level, ELD significantly upregulated key osteogenic markers, with early induction of ALP and COL1A1 followed by subsequent increases in ON and BSP expression (p < 0.05). These molecular changes were associated with a significant increase in calcium-rich nodule formation, confirming enhanced mineralization at biologically favourable concentrations. Overall, ELD demonstrated dose-dependent regulatory effects on hDPSC and may represent a promising strategy for regenerative endodontic therapy. ELD promotes osteo/odontogenic differentiation and mineralized matrix formation in hDPSCs through dose-dependent modulation of redox balance and cellular functionality. Together, these findings underscore the presence of a defined therapeutic concentration window and support the potential use of ELD as a biomodulatory molecule in regenerative endodontic approaches.