Cartilaginous differentiation of MDSCs. A (b, d, and f), the control group of cartilaginous differentiation, and were also negative for Alcian blue staining; a, after 1d, MDSCs in the induced group had no difference in the morphology and phenotype; c, the induced group of cartilaginous differentiation. After induction for three weeks, the cells became compressed; e, the cells of induced group were positive for Alcian blue staining (bar=100μm). B (1), marker; 2, GAPDH; 3, COLII+; 4, COLII- (MDSCs); 5, SOX9+; 6, SOX9- (MDSCs); 7, COL-X+; 8, COL-X- (MDSCs); 9, aggrecan+; 10, aggrecan- (MDSCs).