FIG. 4.

(A) Analysis of the expression of relevant cartilaginous markers at transcriptional level from porcine chondrocytes in agarose gel surface and gel bulk by quantitative real-time polymerase chain reaction (PCR) (n = 3). The values represent the levels of expression relative to that of the internal control gene (GAPDH). Gray: cells at surface (n = 3); white: cells in bulk (n = 3). The values represent the means ± standard deviations. The selected time points of analysis are 3, 10, 18, and 32 days, respectively. *Differences between different constructs at the same culture time are not significant (p > 0.05); **differences between different constructs at the same culture time are significant (p < 0.05). (B) Graphical representations of the secretion of extracellular matrix in agarose gel surface and gel bulk. From left to right, the panel illustrates the secretion of GAG and total collagen, respectively, as a function of culture time at 10, 18, and 32 days. The values have been normalized by the dry weights of the gel surface and gel bulk and represent the means ± standard deviations. **Differences between different constructs at the same culture time are significant (p < 0.05).