Figure 4.

Chondrogenic differentiation of adult and infant BMSC. (A) Chondrogenic pellets were generated from adult and infant BMSCs at passages 3–5, with 3 × 10⁵ cells per pellet, and cultured for 21 days. The image shows representative chondrogenic pellets, with a scale bar indicating 1 mm. (B) The diameters of the chondrogenic pellets were measured on day 21. (C) The gene expression of SOX9, (D) COL2, and (E) COL10 in the chondrogenic pellets differentiated from adult and infant BMSCs was analyzed by RT-qPCR from days 7 to 21. The expression values were normalized to the reference gene (GAPDH). The gene expression levels in undifferentiated cells were used as controls for comparison with adult and infant BMSC-differentiated chondrogenic cells, and the results were presented as relative fold changes. The mean ± standard error of the mean (SEM) calculated from three experimental replicates within both the infant and adult groups. Statistical significance between infant and adult BMSC-differentiated pellets was determined using the Mann–Whitney U test. BMSC: bone marrow–derived mesenchymal stem cell; GAPDH: glyceraldehyde-3-phosphate dehydrogenase RT-qPCR: real-time quantitative polymerase chain reaction. The significance levels are indicated by *P < 0.05; **P < 0.01.