Abstract: Objective · To investigate the role of CD8+ T cells in the pathogenesis of acute murine colitis induceddextran sulfate sodium (DSS). Methods · Wild type and CD8 knock-out (CD8-/-) mice with C57BL/6 background were given DSS with concentration of 2% (m/V). The body weight, colon length, pathological changes and disease activity of colitis were observed dynamically. The total RNA was extracted the distal colon of mice after induction for 10 d. The mRNA of inflammatory cytokines Il1b, Il6, Il17a, Ifng, Tnf, Il10 and Tgfb1 were detectedreal-time quantitative PCR. Colon tissue sections were stained with hematoxylin-eosin (H-E) and the changes of intestinal histopathology were evaluated, and the infiltration of CD8+ T cells in colon tissue was observedimmunofluorescence staining. The survival rate of mice was observed with 3% and 4% (m/V) DSS solution-induced colitis models. Results · After CD8-/- mice being induced2% DSS, the body weight decreased slowly and showed an increasing trend on the 9th day, while the pathological changes of colon tissues of CD8-/- mice were slight. The levels of Il1b, Il6, Il17a, Ifng and Tnf mRNA were lower than those of wild-type mice (P+ T cells in colonic lamina propria of wild-type mice with 2% DSS induction was higher than that of wild-type mice without DSS treatment (P0.001). The survival rates of wild-type mice induced3% and 4% DSS were 37.5% and 0, and the survival rates of CD8-/- mice were 66.7% and 100%, while the survival rates of CD8-/- mice receiving 3% and 4% DSS were higher than those of wild-type mice (P0.025, P0.001). Conclusion · CD8+ T cells can promote the development of murine acute DSS-induced colitis.

Key words: CD8+ T cells, dextran sulfate sodium, acute colitis, pathogenesis, mouse