Figure 3: Biochemical analyses were used to detect DNA and GAG amounts in the pellets from expanded SDSCs (A) and chondrocytes (B) after a 14-day serum-free chondrogenic induction. Cell viability was shown as DNA ratio, which was from DNA amount at days 7 and 14 normalized by that at day 0. Cell differentiation was shown as chondrogenic index (ratio of GAG to DNA). Significant differences are indicated as follows: * = p < 0.05; ** = p < 0.01; and *** = p < 0.001. Data are shown as average ± SD for n = 4.