Interleukin-34 deficiency aggravates development of colitis and colitis-associated cancer in mice

Figure 5 Protective effect of interleukin-34 against acute dextran-sodium-sulfate-induced colitis is not dependent on macrophages. A: mRNA expression levels of M1 macrophage markers (iNOS, TNF-α and MCP-1) and M2 macrophage markers [ARG1, MRC2 (CD163)] in the colonic mucosa of IL-34^-/- and WT mice treated with 3% DSS. M2/M1 ratio (CD163/iNOS) was calculated; B: Experimental design. To deplete macrophages, IL-34^-/- and WT mice were treated with Clo-lips 2 d prior to 3% dextran sodium sulfate (DSS) administration and continuing once every 2 d until death (n = 4 per group); C: mRNA expression of macrophage cell marker (F4/80) was detected in colonic mucosa of WT mice treated with Clo-lips (n = 4 per group); D: Clinical score of IL-34^-/- and WT mice treated with 3% DSS and Clo-lips (n = 4 per group); E and F: Colon length of IL-34^-/- and WT mice treated with 3% DSS and Clo-lips (n = 4 per group); G and H: Representative microscopic pictures (G) and histological scores (H) of IL-34^-/- and WT mice fed with 3% DSS and Clo-lips (n = 4 per group); I: mRNA expression of inflammatory cytokines was detected in IL-34^-/- and WT mice treated with 3% DSS and Clo-lips (n = 4 per group). ARG1: Arginase; Clo-lip: Clodronate liposome; CSF1R: Colony-stimulating factor-1 receptor; DSS: Dextran sodium sulfate; IL-34: Interleukin-34; iNOS: Inducible nitric oxide synthase; MCP-1: Monocyte chemoattractant protein-1; MRC2: Mannose receptor C type 2; TNF-α: Tumor necrosis factor-α; WT: Wild-type. Scale bars = 200 μm. Data depict mean ± SD. ^aP < 0.05, ^bP < 0.01, ^cP < 0.005.