Fig. 4
Analysis of cryopreserved dermal fibroblasts. Three independent samples per group were cryopreserved at two cell densities in liquid nitrogen for 9 months in two different formulations based on inactivated human platelet lysate and compared to the commercial products Cryostor® CS10 and STEM-CELLBANKER DMSO FREE-GMP Grade® (SCB). A Cell viability and B recovery post-thaw. C Recovery and D phase-contrast images of cells after 24-h culture (scale bar: 100 µm). E Flow cytometry-based immunophenotype of fresh and thawed cells cryopreserved at 106 cells/ml (left) and 10 × 106 cells/ml (right). F Flow cytometry assessment of collagen type I expression. G Flow cytometry analysis of apoptosis at 106 cells/ml (left) and 10 × 106 cells/ml (right) cryopreservation densities. H Stability analysis of thawed cells kept in cryopreservation solutions at 106 cells/ml (left) and 10 × 106 cells/ml (right) densities. Data are shown as mean ± SEM. Two-way ANOVA: differences between fresh cell values *P < 0.05; ***P < 0.001; differences between solutions #P < 0.05; ##P < 0.01; ###P < 0.001