Kynurenine plays an immunosuppressive role in 2,4,6-trinitrobenzene sulfate-induced colitis in mice

Figure 4 TNBS-treatment increased the levels of anti-inflammatory cytokines in the colon of KMO-deficient mice. A: mRNA levels of TGF-β, IL-10, TNF-α, IFN-γ, and IL-17 in the colons of indicated mice were determined by quantitative PCR. B–C: Serial sections of the colons from vehicle or TNBS-treated KMO^+/+ mice and TNBS-treated KMO^+/+ or KMO^−/− mice were stained for TGF-β, IL-10, Foxp3, and DAPI (nuclei). D: The ratio of TGF-β⁺ cells or IL-10⁺ cells to Foxp3⁺ Treg cells in ILF of TNBS-treated KMO^+/+ mice or TNBS-treated KMO^−/− mice. Negative controls for of TGF-β, IL-10 and Foxp3 were not stained (Supplementary Figure 3). The data are represented as mean ± SE from at least four independent experiments: ^aP < 0.05 vs TNBS-treated KMO^+/+ mice group; ^bP < 0.01 vs TNBS-treated KMO^+/+ mice group; ^dP < 0.01 vs KMO^−/− Vehicle group. KMO: Kynurenine 3-monooxygenase; TNBS: Trinitrobenzene sulfonic acid; TGF-β: Transforming growth factor-β; IL-10: Interleukin-10; TNF-α: Tumor necrosis factor-α; IFN-γ: Interferon-γ; IL-17: Interleukin-17; Foxp3: Forkhead boxprotein P3.