Fig. 2: Chemotherapy-induced toxicity depends on the expression of IDO1.

A Schematic diagram showing the process of oxaliplatin toxicity mice model treated with L-kynurenine or PBS control. Changes of body weight (B), clinical score (C), survival rate (D), spleen index (E) and colon length (F). (n = 9 mice for PBS and LK + PBS group, n = 8 mice for OXA group, n = 5 mice for LK + OXA group). G Representative histopathological images of colon (left) and quantification for the gaps between crypt bases and muscularis mucosa (right). Arrows indicate gaps between crypt bases and muscularis mucosa. Scale bar = 100 μm. H Immunohistochemical staining of Ki67 in intestinal tissue. Representative images (left) and the quantification of Ki67 area (right). Scale bar = 20 μm. I Immunofluorescence analysis of TUNEL in intestinal tissues. Representative images (left) and the quantification of TUNEL positive area (right). Scale bar = 50 μm. G–I n = 5 mice for PBS, n = 8 mice for OXA group, n = 5 mice for LK + PBS group, n = 5 mice for LK + OXA group. J Immunofluorescence analysis and transcript expression of MUC2 in intestinal tissues. Representative images (left) and the quantification of MUC2 expression (right). Scale bar = 50 μm. (n = 9 mice for PBS, n = 8 mice for OXA group, n = 9 mice for LK + PBS group, n = 5 mice for LK + OXA group). K Schematic diagram of L-kynurenine metabolism from Tryptophan via IDO1. L Transcript expression of Ido1 in intestinal tissues from mice treated with oxaliplatin and PBS control. n = 6 for control group, n = 5 for OXA group. M Schematic diagram showing the process of Ido1^-/- mice and WT mice treated with oxaliplatin. Changes of body weight (N), clinical score (O), spleen index (P) and colon length (Q). R Representative histopathological images of colon (left) and quantification for the gaps between crypt bases and muscularis mucosa (right). Arrows indicate gaps between crypt bases and muscularis mucosa. Scale bar = 100 μm. S Immunohistochemical staining of Ki67 in intestinal tissue. Representative images (left) and the quantification of Ki67 area (right). Scale bar = 20 μm. T Immunofluorescence analysis of TUNEL in intestinal tissues. Representative images (left) and the quantification of TUNEL positive area (right). Scale bar = 50 μm. U Immunofluorescence analysis and transcript expression of MUC2 in intestinal tissues. Representative images (left) and the quantification of MUC2 expression (right). Scale bar = 50 μm. N–U n = 5 mice for WT group, n = 8 for Ido1^-/- group. Quantitative data are expressed as the mean ± standard error of the mean (S.E.M). *P  <  0.05, **P  <  0.01, ***P  <  0.001, ****P  <  0.0001; ns, not significant. P values were determined by two-way ANOVA with Tukey’s post hoc test (B, C), one-way ANOVA with Tukey’s post hoc test (D–J), two-way ANOVA with Šídák’s multiple comparisons test (N, O) and unpaired two-tailed Student’s t-tests (L, N–U). Source data are provided as a Source Data file.