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

Figure 1 Increased number of F4/80⁺ KMO⁺ cells in the colon exacerbates TNBS-induced colitis. Mice were treated with either TNBS or vehicle, and colons were collected three days after treatment. A: Histological scores determined based on a histological grading as described in Materials and Methods. B: Representative images of H&E-stained colons of the said mice. C, D: The KMO⁺ cells in the colons of the said mice were counted using immunohistochemical staining for KMO. E: KMO mRNA expression in the colon was determined by quantitative PCR. F: The colons of TNBS-treated mice were stained for F4/80, CD19, CD11c, KMO, and DAPI (nuclei) using immunofluorescence staining. The negative controls for F4/80, CD19, CD11c, and KMO were not stained (Supplementary Figure 2 and 3). ^aP < 0.05 vs Vehicle group, ^bP < 0.01 vs Vehicle group, ^cP < 0.05 vs TNBS-treated KMO^+/+ mice group. KMO: Kynurenine 3-monooxygenase; TNBS: Trinitrobenzene sulfonic acid.