Fig. 4

USCs have the potential to differentiate towards osteocytes, chondrocytes and adipocytes. a Osteogenic differentiation: After 28 days of culture in the induction medium, USCs stained positive for Alizarin red in contrast to the un-induced control. Representative images are shown. b mRNA expression of Osteocalcin relative to GAPDH was analyzed by qPCR. Induced cells showed a significant increase compared to the un-induced control (p = 0.05). Error bars indicate the standard deviation from three biological replicates (three different donors). Con. control, Ind. induced. c Chondrogenic differentiation: representative pictures showing morphological changes and alcian blue positive staining of USCs after 28 days of induction, compared to an un-induced control, are depicted. d The chondrogenic marker Collagen X (Coll. X) could only be detected in induced cultures by semi-quantitive PCR. GAPDH was used as loading control. Numbers represent different donors, I induced, C control, L 100 bp ladder. All bands are at the expected heights. e Adipogenic differentiation: USCs and ASCs were subjected to adipogenic differentiation for 24 days. Uninduced cells served as control. The formation of lipid droplets was visualized by Oil Red O staining. Representative images are shown