Fig. 1

BNTA was identified as a strong chondrogenic inducer that increased anabolism of chondrocytes in vitro. a Pie chart of the small compounds library used for screening in different functional groups. b Schematic diagram of screening system using alcian blue staining and reverse transcription polymerase chain reaction (RT-PCR) verification. c Structure of BNTA. d Alcian blue staining of ATDC5 cells after incubation with BNTA or DMSO (vehicle) at 10 μM for 5 d (n = 3; three independent experiments; scale bars, 400 μm). e Cell viability of human osteoarthritis chondrocytes assessed using the alamar blue assay at 1 d, 3 d, 5 d, and 7 d after BNTA treatment (n = 14 for each group; 1 d, nonparametric test; 3 d, 5 d, and 7 d, one-way ANOVA). f Quantification of mRNA levels for collagen type II alpha 1 chain (COL2A1), aggrecan (ACAN), proteoglycan 4 (PRG4), and SRY-box 9 (SOX9) in human OA chondrocytes treated with BNTA for 6 h. Fold changes relative to vehicle control are shown (n = 6 for each group; COL2A1, ACAN, SOX9, one-way ANOVA; PRG4, nonparametric test; three independent experiments). g The mRNA levels of Col2a1, Acan, Prg4, and Sox9 in interleukin 1 beta (IL1β, 10 ng ml⁻¹)-induced rat OA chondrocytes treated with BNTA for 6 h (n = 6 for each group; Col2a1, one-way ANOVA; Acan, Prg4, and Sox9, nonparametric test; three independent experiments). h The proteins levels of SOX9 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in human OA chondrocytes treated with vehicle or BNTA (0.1 μM) for 2d. i The proteins levels of COL2A1, SOX9, and GAPDH were detected using western blotting assay in IL1β (10 ng ml⁻¹)-induced rat OA chondrocytes treated with or without BNTA (0.1 μM) for 2d. All data are shown as the mean ± standard deviation (s. d.). *P < 0.05, **P < 0.01, ***P < 0.001. Source data are provided as a Source Data file