Dental pulp stem cell responses to electric field stimulation: A pilot in vitro study with potential implications for dentin-pulp regeneration

OBJECTIVE: To investigate the in vitro effects of electric field (EF) stimulation on the proliferation, migration, stemness, and differentiation potential of dental pulp stem cells (DPSCs), and to explore its potential relevance to dentin-pulp regeneration. METHODS: DPSCs were exposed to EF strengths of 100, 200, or 300 mV/mm. Proliferation was assessed by Cell Counting Kit-8 (CCK-8) assay. Cell migration and electrotaxis were evaluated by scratch assay and live-cell imaging, respectively. Stemness-associated gene expression was analyzed by quantitative polymerase chain reaction (qPCR). Following EF pre-stimulation, the osteo/odontogenic, angiogenic, and neurogenic differentiation potential of DPSCs was examined using staining assays, tube formation analysis, qPCR, western blotting, and immunofluorescence staining. RESULTS: EF stimulation at 200 and 300 mV/mm increased DPSC proliferation at 72 h, whereas 100 mV/mm showed no significant effect. EF exposure transiently reduced scratch closure at 48 h. Live-cell tracking showed anodal migration, with 100 mV/mm producing the highest migration speed and efficiency. EF stimulation dynamically regulated KLF4, NANOG, OCT4, and SOX2 expression in a time-dependent manner. Moreover, EF pre-stimulation enhanced osteo/odontoblastic differentiation, alkaline phosphatase (ALP) activity, mineralization, and DSPP, DMP1, and OPN expression, while promoting angiogenesis through increased CD31, VEGF, and FGF2 expression and tube formation. However, EF did not further promote neurogenic differentiation, as NES and MAP2 expression and cell morphology remained unchanged after neural induction. CONCLUSION: Under the tested in vitro conditions, EF stimulation regulated DPSC proliferation, electrotaxis, and stemness-associated gene expression and selectively enhanced osteo/odontogenic and angiogenic, but not neurogenic, differentiation potential. CLINICAL SIGNIFICANCE: Electrical stimulation can enhance the stemness of dental pulp stem cells while modulating their proliferation, migration, osteo/odontogenic differentiation, and angiogenic potential. Collectively, these findings provide experimental support for optimizing the clinical application of endodontic electrical devices, advancing electrical stimulation-based therapeutic strategies, and ultimately improving outcomes in dentin-pulp regeneration.