Fig. 2

UPR-related gene/protein expression in four groups. a Quantitative RT-PCR for ATF6, ATF4, and XBP1 of the four groups in the cultured constructs on 0, 7, 14, and 21 days. These data were normalized to GAPDH. b Western blot results for ATF4, ATF6, XBP1, and COL2A1 at different culture times. COL2A1 was not detectable at 0 day; β-actin was used as a loading control. c Normalized expression of ATF4, ATF6, XBP1, and COL2A1 in response to Western blot analysis. d Immunofluorescence staining of ATF4, ATF6, and XBP1 at 0 days. Scale bar: 50 μm. The values were means ± S.D.; * indicate P < 0.05, ** indicate P < 0.01, *** indicate P < 0.001