Fig. 1

Ipriflavone promoted the proliferation and reduced the apoptosis of human chondrocytes. A, The results of the immunofluorescence assay showed that the cells (primary human chondrocytes were incubated in DMEM supplemented with 10% FBS in the presence or absence of ipriflavone) were positive for type II collagen and negative for type I collagen staining (red, scale bar: 100 μm), and the cultured cells maintained their chondrocytes phenotype. B-a, The EdU-based cell proliferation assay showed that compared with the DMSO group, and the EdU-positive cells (red, scale bar: 100 μm) were significantly increased in both the 5 μM and 10 μM IP treatment groups. B-b, The percentage of EdU-positive cells was quantified, and the proliferation of chondrocytes was significantly increased in both IP treatment groups. Data are expressed as means ± SDs (n = 6) ***P < 0.001 versus the DMSO group. B-c, The CCK-8 assay results showed that the viability of chondrocytes was higher in both IP treatment groups than the DMSO control group, and the viability gradually increased with a longer treatment time. Thus, IP significantly promotes the proliferation of human chondrocytes in vivo. C, The Annexin V-FITC/propidium iodide (PI) dual staining assay by flow cytometry indicated that apoptosis was reduced in the IP treatment group compared with the DMSO control group at 48 h after treatment. Values are the mean ± SDs. (n = 3) *P < 0.05 versus the DMSO group