Fig. 3: IL-33 facilitates the progression of arthritis in collagen antibody-induced arthritis mice, accompanied by NET production.

a Flowchart of the animal experimental procedures created using BioRender.com. DBA/1J mice received 1.5 mg/mouse type II collagen mAbs via the tail vein on Day 0. On Day 3, 50 µg of LPS was injected via the tail vein to synergize with the mAbs for arthritis development. The mice were also administered 1 µg of IL-33 intraperitoneally for five consecutive days. b Inflammatory scores of CAIA mice treated with IL-33 (n = 5) or the solvent control (n = 5). c Representative H&E, safranin O, and toluidine blue staining of joint tissue from IL-33-treated CAIA mice. d, e Representative micro-CT images and radiological scores of bone erosion in IL-33-treated CAIA mice. f Peripheral serum levels of citH3-DNA in CAIA mice. g Representative immunofluorescence image of joint tissue from IL-33-treated CAIA mice. All the data are presented as the means ± SDs, *p < 0.05.