Abstract
Aim: This study examined the impact of direct current electric fields (DCEFs) on the biological properties of stem cells derived from the apical papilla (SCAP) and further elucidated the underlying mechanisms involved in odontogenic differentiation induced by DCEFs stimulation. Methodology: The measurement of endogenous currents in wounded dentine was achieved using a non-invasive vibrating probe system. Two-dimensional (2D) and three-dimensional (3D) systems were developed to apply DCEFs of varying strengths. The migration direction and trajectories of SCAP within DCEFs were analysed using time-lapse imaging. Cell proliferation was assessed through Hoechst staining and the CCK-8 assay. Changes in cell morphology, arrangement, and polarization were examined using fluorescence staining. The odontogenic differentiation of SCAP in vitro was assessed using quantitative polymerase chain reaction (qPCR), western blot analysis, alkaline phosphatase staining, and Alizarin Red S staining. In vivo evaluation was conducted through Haematoxylin and eosin staining, immunohistochemistry staining, and Sirius Red staining after transplantation experiments. Results: Injured dentine demonstrated a significantly increased outward current, and DCEFs facilitated the migration of SCAP towards the anode. DCEFs at a magnitude of 100 mV/mm promoted SCAP proliferation, whereas DCEFs at 200 mV/mm enhanced both polarization and odontogenic differentiation of SCAP. The application of cytoskeletal polymerization inhibitors mitigated the odontogenic differentiation induced by DCEFs. In vivo studies confirmed that DCEFs promoted the differentiation of SCAP into odontoblast-like cells in an orderly arrangement, as well as the formation of collagen fibres and dentine-like tissue. Conclusions: DCEFs of varying intensities exhibited an enhanced capacity for migration, proliferation, odontogenic differentiation, and polarization in SCAP. These findings provide substantial insights for the advancement of innovative therapeutic strategies targeting the repair and regeneration of immature permanent teeth and dentine damage.