PPARG and clostridium difficile infection: To further investigate the changes of PPAR-γ and occludin expression in the mice with CDI, we performed immunofluorescent staining to show their distribution in C. difficile-infected colonic tissues and found that PPAR-γ was mainly expressed in the ECs of colonic tissues, while occludin was expressed at the lateral side of the adjacent ECs (Figure 1D).