Fig. 5

Improving freeze–thaw tolerance through pre-treatment. a Flow cytometric analysis of synovial MSCs and HUVECs after freeze-thawing by forward scatter (FSC) and side scatter (SSC), stained with FITC-caspase-3/7 and V500-SYTOX™ blue dead cell stain. b Live cell rate of synovial MSCs and HUVECs. Cells negative for FITC and V500 were considered live cells. Mean values and SD are shown (n = 6). The p value was calculated using the Mann–Whitney test. c Colony forming units (CFUs) of synovial MSCs and HUVECs after freeze-thawing. Representative dishes stained with crystal violet. d CFUs after 12 days in culture before and after freeze-thawing. Mean values and SD are shown (n = 18). e Colony area after 12 days in culture before and after freeze-thawing. Mean values and SD are shown (n = 12). Thawed: cells immediately after freeze-thawing. The p value was calculated using the Kruskal–Wallis test with Steel–Dwass multiple comparisons test