Fig. 6

Effects of parkin deficiency of inflammatory bone erosion in a K/BxN serum-transfer arthritis mouse model. A, B Adult K/BxN mice were bled, and the sera were pooled. WT and Parkin^−/− mice were intraperitoneally injected on days 0 and 2 with 200 µl of pooled K/BxN. Arthritis was A clinically scored, and B paw thickness was measured with a caliper for up to 13 days. The means ± SD of five mice per group are shown. C Ankle joints of K/BxN serum-transfer arthritis model mice were stained with hematoxylin/eosin (H/E) or toluidine blue (blue). Immunohistochemical analysis was performed to detect F4/80 (brown). The arrows indicate bone-destructed loci of ankle joints (middle) or F4/80⁺ macrophages (right), respectively. D Synovitis, pannus, and erosion scores were quantified. E Parkin deficiency enhances the bone-resorption capacity. Quantitative histomorphometry of the distal femur of K/BxN-induced WT and Parkin^−/− mice (n = 4–7). Bone volume per tissue volume (BV/TV) (left), structure model index (SMI) (middle), and total porosity (%) (right) values were measured by peripheral quantitative computed tomography. Data represented as means ± SD. *P < 0.05 and ***P < 0.001 between the indicated groups. P-values were calculated by Kruskal–Wallis or Tukey post hoc comparison tests