After receiving FMT treatment, mice with colitis showed significant improvements in body weight loss, disease activity index (DAI) scores, shortening of colon length, colonic histopathology, and colonic tight junction proteins (TJPs, Claudin-1 and ZO-1) (P < 0.05), although there were still differences compared with the CON group (P < 0.05) (Fig. 1, E–J). This evidence concerns the gene CLDN1 and colitis.