Low-Intensity Electric Field Stimulation Modulates Proliferation, Stemness, and Chondrogenesis of Tonsil-Derived Mesenchymal Stem Cells.

BACKGROUND

Electric field (EF) stimulation is an emerging biophysical approach that enhances stem cell function by mimicking endogenous wound currents. However, its effects on tonsil-derived mesenchymal stem cells (TMSCs) remain poorly understood.

METHODS

A low-intensity EF stimulation system (0-12 mV; potential difference between parallel electrodes, 5 mm apart; 5 min on/5 s off for 38 h) was established to examine the effects of EF on TMSC viability, proliferation, stemness, and chondrogenic differentiation. Young and senescent TMSCs were evaluated for metabolic activity, cell cycle distribution, and expression of stemness- and chondrogenesis-related markers. For differentiation assays, cells were preconditioned with EF stimulation before chondrogenic induction.

RESULTS

Moderate EF intensities (4-8 mV) enhanced the viability, metabolic activity, and proliferation of both young and senescent TMSCs, whereas excessive stimulation (12 mV) reduced these functions without causing cell death. In senescent TMSCs, EF stimulation promoted S-phase entry and upregulated Cyclin A2 and Cyclin B1 expression, suggesting partial restoration of proliferative potential. In young TMSCs, EF stimulation increased NANOG, OCT4, and SOX2 expression, thereby supporting stemness maintenance. EF stimulation enhanced glycosaminoglycan deposition and chondrogenic marker expression (Aggrecan, COL2A1, and SOX9) when applied before chondrogenic induction but exerted an inhibitory effect when applied during the differentiation phase.

CONCLUSION

Low-intensity EF stimulation serves as a tunable bioelectric cue that enhances the proliferation, stemness, and early chondrogenic potential of TMSCs in an intensity- and state-dependent manner, providing a non-invasive strategy to improve mesenchymal stem cell function for regenerative applications.