The role of Th17/Treg balance and Th22 cell in the pathogenesis of DSS-induced colitis in mice

T-helper (Th) cells play a critical role in inflammatory bowel disease (IBD), especially the two new types: Th17 and Th22. But whether they are protective or pathogenic in the gut is still controversial. Unlike them, regulatory T (Treg) cells have undoubtedly suppressive function and can maintain immune homeostasis. Our current aims were to examine the change of Treg/Th17 balance, Th22 proportion, and the expression of Th17-related and/or Th22-related cytokines in inflammatory bowel disease. In this study, 3% dextran sulphate sodium (DSS) was administered orally to C57BL/6 mice to induce colitis. The morbidity was evaluated by daily body weight, colon length, disease activity index, and histology score of colonic lesions. Th17, Th22, and Treg cells were measured using flow cytometry. IL-17A, IL-17F, and IL-22 were quantified using enzyme linked immunosorbent assay (ELISA) kits. DSS administration induced severe clinical manifestations, such as body weight loss, colon shortening, relatively high disease ac...