Fig 2: The level of the IL‐37 protein was detected in clinical specimens from patients with bone infections. The exogenous administration of IL‐37 attenuated LPS‐induced inflammatory bone destruction in mice. (a) Four groups of samples were obtained noninfectious fractures and traumatic osteomyelitis‐infected samples. Samples (Birt et al., 2017; Mbalaviele et al., 2017; Takayanagi, 2009; Wojdasiewicz et al., 2014) were extracted from normal cancellous bone, infected cancellous bone, normal connective tissue, and infected connective tissue, respectively. Levels of IL‐37 (IL‐37b) and GAPDH were detected by immunoblotting. (b) Representative images of H&E staining and immunohistochemical staining. Arrows indicate IL‐37‐positive cells. Scale bar = 200 μm. (c) TRAP staining, immunohistochemical staining, and H&E staining in sections of calvarial bones from 6‐week‐old C57BL/6 mice treated with PBS, LPS, or LPS + IL‐37b. Arrows indicate TRAP‐positive cells. Scale bar = 400 μm; N = 4. (d) The 3D images, images of longitudinal sections, images of cross‐sections, and trabecular images were reconstructed at the distal femur. Quantification of Tb.Sp. and BV/TV in each group. Scale bar = 1 mm; N = 4. BV/TV: bone volume per tissue volume; Ctrl: control; ES/BS: eroded surface per bone surface; GAPDH: glyceraldehyde 3‐phosphate dehydrogenase; H&E: hematoxylin and eosin; IL‐37: interleukin‐37; LPS: lipopolysaccharide; PBS: phosphate‐buffered saline; Tb.Sp.: trabecular spacing; TRAP: tartrate‐resistant acid phosphatase [Color figure can be viewed at wileyonlinelibrary.com]