Figure 4.

Effect of melatonin on oxazolone (Oxa)-induced colitis depends on gut microbiota. (A) Weight changes and colon length (B, C) in co-housed mice at day 1 after 3% oxazolone enema. (D–F) Representative H&E staining of colonic sections (×20) and pathological score of inflamed colonic tissue. (G, H) Flow cytometry analysis of colonic CD45⁺CD11b⁺Ly6G⁺ neutrophil subsets in co-housed mice at day 1 after 3% oxazolone enema. (I, J) qPCR of Tnfa and Il-1b mRNA in colonic tissues in co-housed mice at day 1 after 3% oxazolone enema (all values were normalized to the melatonin-untreated group). (K–M) Immunoblot and densitometric analysis of ZO-1 and occludin in co-housed mice. Data are representative of at least two independent experiments. Data are shown as mean ± SD. ns, no significance.