Glycosaminoglycan production detected in the differentiated human umbilical cord mesenchymal stromal cells cultured in Matrigel™. Human umbilical cord mesenchymal stromal cells were cultured for 1 to 21 days in a three-dimensional Matrigel™ system. (A) Histological staining for proteoglycan by safranin O (n = 4, only one represented image shown; scale bar = 50 μm). (B) Sulfated glycosaminoglycan production normalized to DNA content (sGAG/DNA, n = 4, mean ± standard error) in cells (a, significant difference was detected between either treatment groups and control at day 21 only, one-factor analysis of variance, followed by Tukey’s post-hoc analysis, P < 0.05). IGF-1, insulin-like growth factor-1; TGF, transforming growth factor.