Figure 7.

Myeloid-specific deletion of MYC mitigates in vivo osteoclast formation and bone erosion of NRF2-deficient mice in mouse arthritis model. Arthritis was induced by the K/BxN serum transfer method in 8- to 9-week-old male WT, NRF2-deficient (NRF2 KO), myeloid-specific MYC/NRF2-deficient (MYC^ΔM/NRF2 DKO) mice. (A) Schematic timeline of the experiment design. The arthritis-inducing serum was injected into the mice intraperitoneally (IP) on day 0 and 2. (B) Time course of the clinical score and swelling of joints during the progression of arthritis. Data are shown as mean ± s.e.m. of at least five mice per group. * p < 0.05 between NRF2 KO and MYC^ΔM/NRF2 DKO groups using two-way ANOVA. (C) TRAP staining of histological sections of tarsal bones from WT, NRF2 KO, or MYC^ΔM/NRF2 DKO arthritic mice. Squares show enlarged images. Left scale bar: 400 μm. Right scale bar: 100 μm. (D) Histomorphometric analysis of the tarsal bones. Erosion over bone surface (ES/BS). Osteoclast surface area per bone surface (Oc.S/BS). Osteoclast number per bone surface (Oc.N/BS). Data are shown as mean ± s.e.m of at least five mice per group. * p < 0.05 using one-way ANOVA; NS, not significant.