Nanostructured substrate conformation can decrease osteoblast-like cell dysfunction in simulated microgravity conditions

Cells in situ are surrounded with defined structural elements formed by the nanomolecular extracellular matrix (ECM), and at the same time subjected to different mechanical stimuli arising from variety of physiological processes. In this study, using a nanotextured substrate mimicking the structural elements of the ECM and simulated microgravity, we wanted to develop a multifactorial model and understand better what guides cells in determining the morphological cell response. In our set-up, bone precursor cells from rat bone marrow were isolated and cultured on nanotextured polystyrene substrate (pitch 200 nm, depth 50 nm). Simulated microgravity was applied to the cells, using a random positioning machine (RPM). The results demonstrated that cells cultured on nanotextured substrate align parallel to the grooves and re-align significantly, but not completely, when subjected to simulated microgravity. The nanotextured substrate increased cell number and alkaline phosphatase (ALP) activity, whereas simulated microgravity decreased cells number and ALP activity. When the nanotextured substrate and simulated microgravity were combined together, the negative effect of the simulated microgravity ALP and cell number was reversed. In conclusion, absence of mechanical load in simulated microgravity has a negative effect on initial osteoblastogenesis, and nanotextured surfaces can partly reverse such a process.