Fig. 3: Sirt6 contributes to aging and injury-induced chondrocyte senescence.
From: Sirt6 attenuates chondrocyte senescence and osteoarthritis progression
a–c Representative images of immunofluorescence of p16INK4a, p21, p53, HMBG1, IL-1β, and SA-β-Gal staining in cultured chondrocytes from 6-month-old mice (Sirt6flox/flox and Sirt6 cKO) (a), 12-month-old mice (Sirt6flox/flox and Sirt6 cKO) (b), and 18-month-old mice cartilage tissues (Sirt6flox/flox and Sirt6 cKO) (c), respectively. n = 6 mice per group. d Representative images of Safranin O staining of cartilage tissues (medial femoral condyle) from 6-month-old mice (Sirt6flox/flox and Sirt6 cKO), 12-month-old mice (Sirt6flox/flox and Sirt6 cKO), and 18-month-old mice (Sirt6flox/flox and Sirt6 cKO) and OARSI. n = 6 mice per group. e Synovial inflammation of 6-month-old mice (Sirt6flox/flox and Sirt6 cKO), 12-month-old mice (Sirt6flox/flox and Sirt6 cKO), and 18-month-old mice (Sirt6flox/flox and Sirt6 cKO). n = 6 mice per group. f Representative images of Safranin O/fast green staining in cartilage tissues (medial femoral condyle) from the indicated groups (WT, Sirt6flox/flox, and Sirt6 cKO mice undergoing sham or DMM surgery) and OARSI. n = 6 mice per group. g Representative images of immunohistochemistry of p16INK4a, IL-6, p21, p53, IL-β, TNF-α, and HMGB1 in cartilage tissues (medial femoral condyle) from the indicated groups (WT, Sirt6flox/flox and Sirt6 cKO mice subjected to DMM surgery) at 8 weeks post-surgery. n = 6 mice per group. h Chondrocytes apoptosis was assayed by flow cytometry in the indicated groups (WT, Sirt6flox/flox, and Sirt6 cKO mice subjected to DMM surgery). n = 6 independent biological replicates per group. Scar bar: d–f 50 μm, a–c, g 20 μm. Data were presented as the mean ± s.e.m (a–c, g, h) or median (25–75th percentiles) (d–f). P values are from two-tailed unpaired Student’s t-test (c, p16INK4a, p53, HMBG1, IL-1β, and SA-β-Gal levels in a, p16INK4a, p21, p53, HMBG1, and IL-1β levels in b), two-tailed unpaired t-test with Welch’s correction (p21 level in a, SA-β-Gal level in b), two-tailed Mann–Whitney U-test (d–f) or one-way ANOVA test followed by Tukey’s post hoc test (g, h). Source data are provided as a Source Data file.
