EFFECT OF PULSED ELECTRO MAGNETIC FIELD ON MSC CHONDROGENESIS

Abstract

Pulse electromagnetic fields (PEMFs) have been shown to modulate MSC derived chondrogenesis but with inconsistent outcomes. In this study, the effects of precisely specified PEMF signals over MSC chondrogenesis in terms of pulse amplitude, duration and dosage was characterized. It was demonstrated that, contrary to the conventional practice of administering prolonged and repetitive pulsing, MSCs undergoing chondrogenesis are preferentially responsive to an electromagnetic optimal window of low intensity (2mT) exposed for a brief period (10 minutes), administered only once at the onset of chondrogenic induction. On the other hand, multiple pulses administered within a single week, or individually on a weekly basis, diminished chondrogenic outcome. PEMFs were shown to recruit cellular mechanotransduction signaling cascades by stimulating TRP channel-mediated calcium entry to a specified level before chondrogenic outcome is adversely influenced. Lastly, PEMF-induced MSC secretome exerted a paracrine effect to MSC chondrogenesis, which was dependent on the pulsing conditions as well as the MSC culture platform, indicating that cell morphology, cell-cell and cell-matrix interaction might have an influence on the secretome profiles. The observed efficacy of the optimized low amplitude pulsing magnetic fields over MSC-induced chondrogenesis has wide implications for the clinical translation of PEMF-based therapeutic strategies for cartilage regenerative medicine.