Vitrification and slow freezing result in reduced F-actin-content.

(A) Boxplots show the difference of F-actin-content between identical cells before and after cryopreservation with varying recovery time. Non-cryopreserved cells have been incubated for the respective recovery time as a control. Horizontal bars represent the median, box size is defined by the 25th and 75th percentiles. Significant differences based on Mann-Whitney-U test with p-values smaller than 0.05 are indicated by *. (B) Cells, being classified in class II or III, are separated, depending on whether F-actin-content increased or decreased after cryopreservation. The top x-axis states the recovery time in min. (C) Representative actin cytoskeletons of hMSCs with reduced F-actin-content after cryopreservation are shown with their related Δν-value. Images were captured with CLSM. Scale bar indicates 20 μm. For better visualization, contrast and brightness of the presented images were adjusted.