Fig. 5

Chondrogenesis of the BMSCs induced by various concentrations of KGN for 2 weeks. a, f, k, p KGN concentration is 0 nM. b, g, l, q KGN concentration is 1 nM. c, h, m, r KGN concentration is 10 nM. d, i, n, s KGN concentration is 100 nM. e, j, o, t KGN concentration is 1000 nM. a–e The images were obtained by alcian blue staining. f–j The images were obtained by safranin O staining. k–t The images were obtained by toluidine blue staining. The images of p, q, r, s, and t were the enlarged box areas in the images of k, l, m, n, and o. All three stainings indicated that BMSCs were differentiated into chondrocytes induced by KGN in a concentration-dependent manner. KGN also induced morphology change of some BMSCs from spindle shape (black arrow in p) to round shape (yellow arrows in q–t). u The chondrocyte-related gene expression in the KGN-treated BMSCs examined by qRT-PCR. Both collagen II and Sox-9 gene levels were increased in the KGN-treated BMSCs in a concentration-dependent manner. White bars 100 μm; yellow bars 20 μm