Alternating current electrical stimulation promotes the osteogenic differentiation of human periodontal ligament stem/stromal cells.

Electrical stimulation (ES) has shown promise in enhancing the osteogenic differentiation of human stem cells in several tissue engineering (TE) strategies. However, ES effects on human periodontal ligament stem/stromal cells (hPDLSCs) remain unexplored. This study represents the first investigation of ES on hPDLSCs, aiming to establish an optimized protocol and evaluate its effects on proliferation and osteogenic differentiation. Electrical parameters, including voltage, frequency, waveform, and regimen, were optimized, with ES applied 2 h/day for 7 days. The optimal condition for osteogenic differentiation was 3 V/cm, 100 Hz, square waveform, and daily stimulation. Long-term effects were assessed over 21 days under osteogenic induction conditions. Our results showed that ES increased alkaline phosphatase (ALP) activity and calcium deposition, with histological staining confirming mineralization. Alveolar bone-related extracellular matrix (ECM) proteins, including COL I, ASP, OPN, OC, and POSTN, were positively expressed after ES. Expressions of periodontal/bone-specific genes ALP, OPN, and POSTN were upregulated, while the transient transcription factors RUNX2 and OSX were downregulated after ES exposure for 21 days. Overall, this study demonstrates, for the first time, the osteogenic potential of ES on hPDLSCs, providing foundational knowledge for future periodontal TE applications, in particular targeting alveolar bone regeneration.