Cartilage matrix gene expression in engineered cartilage constructs analyzed by real-time, quantitative RT-PCR after Days 14, 28 and 42, respectively. MSC-nanofiber constructs were cultured in chondrogenic medium containing TGF-β1 alone or TGF-β1/IGF-I. Gene expression was analyzed by real-time RT-PCR for (A) aggrecan, (B) collagen type II, (C) collagen type I, and (D) elastin. mRNA values of each gene were normalized to those of the housekeeping gene, G3PDH. All values were mean ± SD. Data were analyzed using two-way ANOVA. Aggrecan, collagen type II, collagen type I, and elastin gene expression changed as a function of culture time (p<0.001 for aggrecan and collagen type II, p<0.05 for collagen type I, p<0.005 for elastin). Compared to TGF-β1 cultures, TGF-β1/IGF-I cultures did not show significant change of levels of mRNA expression of any of these markers (p>0.05).