Cultivation and spontaneous differentiation of rat bone marrow-derived mesenchymal stem cells on polymeric surfaces

Accumulating evidence demonstrated many physical and chemical cues from the local microenvironment could influence mesenchymal stem cells (MSCs) maintenance and differentiation. In this study, we systematically investigated the interaction of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and polymeric substrates. Adhesion, proliferative capacity, cytoskeleton alteration, cytotoxicity, apoptosis, senescence, and adipogenesis potential of rBMSCs were determined on these polymeric inserts prepared from polyetherurethane (PEU) and poly(ether imide) (PEI). Inserts for culture plates were applied to ensure that the rBMSCs were solely in contact to the tested material. The explored inserts exhibited advancing contact angles of 84° (PEU) and 93° (PEI). Finally, the micromechanical properties determined by atomic force microscopy (AFM) indentation varied in the range from 6 GPa (PEU) to 13 GPa (PEI). We found that both PEU and PEI showed a good cell compatibility to rBMSCs. rBMSCs could adherent on both polymeric surfaces with the similar adhesion ratio and subsequent division rate. However, cells cultured on PEU exhibited higher apoptosis level and senescence ratio, which resulted in lower cell density (22061 ± 3000/cm(2)) compared to that on PEI (68395 ± 8000/cm(2)) after 20 days cultivation. Morphological differences of rBMSCs were detected after 5 days cultivation. Cells on PEU exhibited flat and enlarged shape with rearranged filamentous actin (F-actin) cytoskeleton, while cells on PEI and tissue culture plate (TCP) had similar spindle-shape morphology and oriented F-actin. After 20 days, lipid droplets were spontaneously formed in rBMSCs on PEU and PEI but not on TCP. Both PEU and PEI might trigger rBMSCs towards spontaneous adipogenic commitment, whereas PEI provided better cell compatibility on rBMSCs apoptosis, senescence and proliferation.