Fig. 5

Differentiation potential of SBA-derived cKIT⁺ AFSCs into chondrogenic lineage in vitro in a 2D system. (a–f) Alcian Blue staining of SBA-derived cKIT⁺, cKIT⁻, and unsorted amniotic fluid cells cultured in (a, c, e) expansion medium as well as (b, d, f) 4 weeks after induction with chondrogenic differentiation medium. After chondrogenic differentiation cKIT⁺ cells displayed blue-stained deposits of GAGs. By contrast, Alcian Blue stain was less intense in cKIT⁻ and unsorted amniocytes. (g, h) ASCs and (i, j) human chondrocytes were used as a positive control. (k–t) Safranin O staining of SBA-derived cKIT⁺, cKIT⁻, and unsorted amniotic fluid cells cultured in (k, m, o) expansion medium as well as (l, n, p) 4 weeks after induction with chondrogenic differentiation medium. Safranin O staining was less pronounced in cKIT⁻ and unsorted amniocytes as compared to the cKIT⁺ AFSCs following the chondrogenic induction. (q, r) ASCs and (s, t) human chondrocytes were used as a positive control. Insets represent macroscopic pictures of cells on culture plastic stained with Alcian Blue/Safranin O. Scale bars: 500 μm. (u–v) Quantification of (u) Alcian Blue and (v) Safranin O positively stained area in donor matched cKIT⁺ AFSCs, cKIT⁻ amniocytes, unsorted amniocytes before and following chondrogenic induction. ASCs and chondrocytes were used as a control. Data are presented as mean ± standard deviation (SD) (n = 2). Two-way Anova with Šídák’s multiple comparisons test was used to calculate significance. Stars indicate statistical significance, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001, ns p > 0.05.