Although the protein levels of ZO-1 could not be detected by western blot analysis due to the limitations of the antibody utilized in the current study, immunofluorescence staining results demonstrated that ZO-1 expression in the colon was reduced by STZ, suggesting that T1D also induces ZO-1 downregulation in the colon. The gene discussed is TJP1; the disease is type 1 diabetes mellitus.