Axiovert m2 imager

To assess whether mechanical strain influences the vitality of NSCs, dead cells were stained with propidium iodide (Life Technologies, Darmstadt, Germany) and counterstained, irrespective of viability, with Hoechst 33342 (Sigma Aldrich; St. Louis, USA) after 24 h of cyclic stretch or cultivated as a control. Images were taken with an upright microscope (Axiovert M2 imager, Carl Zeiss, Germany). Cells were counted randomized.

Live-cell microscopy was performed with an upright microscope (Axiovert M2 imager, Zeiss, Germany). Cells were imaged using a dip-in objective (N-Achroplan 20× (NA 0.5), Zeiss, Germany) from above the chamber to avoid imaging through the relatively thick chamber bottom. Cells were observed while the elastomer chamber was stretched in steps of an amplitude of 4% and 0.5 mm/s velocity. After reaching 28%, the stretch was released from the system, and cells were again observed in the prestretch position. For analysis, cell branches were marked with the ImageJ software, and their lengths were calculated. For cell body analysis, the cell soma was marked with the ImageJ freehand drawing tool.