Effect of electromagnetic fields on the chondrogenic differentiation under microgravity conditions

A combination therapy of electromagnetic fields (EMF) and simulated microgravity (SMG) has not been examined in regenerative medicine of cartilage. In the present study, a bioreactor system using extremely low-frequency EMF and SMG was applied during the chondrogenic differentiation of human mesenchymal stem cells (hMSCs). It was hypothesized that a beneficial effect of EMF regarding chondrogenesis (COL2A) could be combined with an avoiding effect of SMG regarding hypertrophy (COLXA1) of cartilage. Pellet cultures of hMSCs formed cartilaginous tissue under the addition of growth factors (FGF; TGF-beta3). Pure SMG reduced COLXA1 expression but also COL2A expression of hMSCs. Pure EMF showed no gene expression changes of hMSCs during chondrogenic differentiation. Combining EMF/SMG resulted in a re-increase of COL2A but did not reach control levels. The COL2A to COLXA1 ratio of combined EMF/SMG was not significantly different from control levels. The combination therapy of EMF/SMG did not significantly improve the chondrogenic potential of hMSCs. chondrogenic differentiation, electromagnetic stimulation-control, 1 timepoint with/without stimulation.