Figure 7.

Dextran sulfate sodium (DSS)-induced inflammation in WT and IL-22-KO medaka. (A) Hematoxylin/eosin (H&E)-stained anterior intestinal tissue section of WT and IL-22-KO medaka larvae at 1 and 5 days after DSS stimulation. Arrows indicate the changes in tissue architecture upon DSS stimulation. (B) TUNEL staining in the anterior intestine corresponding to the area observed in H&E staining. The red/pink signals indicate the fragmented nuclear signals by apoptosis, and the blue signals represent nuclear staining by DAPI. The red/pink signals were counted in three consecutive sections for three individual larvae (n=3) from each group and were also counted manually under a microscope. IL: intestinal lumen. (A, B) Scale bar: 50 μm. (C–I) Inflammatory bowel disease-sensitive inflammatory cytokine and PI3K-Akt and MAPK signaling pathway genes were significantly downregulated to < 50% of that in DSS-stimulated IL-22-KO medaka, as confirmed by qPCR. (C) il1b, (D) il22, (E) il23r, (F) tnfa, (G) dditl4, (H) fgf19, and (I) hspa5. ***P < 0.001, **P < 0.01, *P < 0.05, +; P < 0.1 (two-tailed Student’s t-test). (C–I) The expression scale shows the relative values when the expression of the naïve WT group was set to 1. Data shown were obtained from a single experiment (n = 7).