TY - JOUR JO - Archives of Medical Science SN - 1734-1922 VL - 14 IS - 3 PY - 2018 ID - Mayer-Wagner2018 TI - Effects of single and combined low frequency electromagnetic fields and simulated microgravity on gene expression of human mesenchymal stem cells during chondrogenesis AB - Introduction : Low frequency electromagnetic fields (LF-EMF) and simulated microgravity (SMG) have been observed to affect chondrogenesis. A controlled bioreactor system was developed to apply LF-EMF and SMG singly or combined during chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in 3D culture. Material and methods : An external motor gear SMG bioreactor was combined with magnetic Helmholtz coils for EMF (5 mT; 15 Hz). Pellets of hMSCs (±TGF-3) were cultured (P5) under SMG, LF-EMF, LF-EMF/SMG and control (1g) conditions for 3 weeks. Sections were stained with safranin-O and collagen type II. Gene expression was evaluated by microarray and real-time polymerase chain reaction analysis. Results : Simulated microgravity application significantly changed gene expression; specifically, COLXA1 but also COL2A1, which represents the chondrogenic potential, were reduced (p < 0.05). Low frequency electromagnetic fields application showed no gene expression changes on a microarray basis. LF-EMF/SMG application obtained significant different expression values from cultures obtained under SMG conditions with a re-increase of COL2A1, therefore rescuing the chondrogenic potential, which had been lowered by SMG. Conclusions : Simulated microgravity lowered hypertrophy but also the chondrogenic potential of hMSCs. Combined LF-EMF/SMG provided a rescue effect of the chondrogenic potential of hMSCs although no LF-EMF effect was observed under optimal conditions. The study provides new insights into how LF-EMF and SMG affect chondrogenesis of hMSCs and how they generate interdependent effects. AU - Mayer-Wagner, Susanne AU - Hammerschmid, Florian AU - Blum, Helmut AU - Krebs, Stefan AU - Redeker, Julia I. AU - Holzapfel, Boris M. AU - Jansson, Volkmar AU - Müller, Peter E. SP - 608 EP - 616 DA - 2018 DO - 10.5114/aoms.2016.59894 UR - http://dx.doi.org/10.5114/aoms.2016.59894 ER -