Fig. 3

Chondrogenic-related gene/protein expression in four groups. a Quantitative RT-PCR for ACAN, SOX9, COL2A1, and COL1A1 of the four groups in the cultured constructs on 7, 14, and 21 days. These data were normalized to GAPDH. b Immunofluorescence staining of COL2A1 after 21 days of chondrogenic induction. Scale bar: 25 μm. c The semi-quantitative analysis of positive staining of COL2A1 in response to Fig. 3 b. d MTT assay was used to analyze cell proliferation of the four groups: P0 BMSCs, P0 + 4-PBA, P3 BMSCs and P3 + TM. e The DNA and GAG contents were stained for the Hoechst 33258 and dimethylmethylene blue dye binding assays, respectively, after 7, 14 and 21 days of chondrogenic induction, and the absorbances were measured to quantify the contents of DNA and GAG. The left panel shows the DNA content and the right panel shows the ratio between GAG and DNA content. f GAG production was examined using Safranin-O staining in the four samples: P0 BMSCs, P0 with 4-PBA treatment, P3 BMSCs and P3 with TM treatment at 21 days. Scale bar: 100 μm. The values are means ± S.D.; * indicate P < 0.05, ** indicate P < 0.01, *** indicate P < 0.001