Objective To investigate the role of Th17 cells and related cytokines in Helicobacter pylori(H.pylori) infection.Methods To establish a mouse model of H.pyloriinfectious gastritis.Meanwhile,a treatment group and control group were set up.The histological changes in the gastric mucosa were observed and scored under light microscopy;The expression of IL-17 and IL-23 mRNAs as well as protein in gastric tissue was detected by RT-PCR and ELISA,respectively;Th17 cells in mice splenocyte were evaluated using the flow cytometry (FCM) method.Results We found significantly higher levels of IL-17 and IL-23 protein and mRNA levels in supernatant of gastric tissue homogenates of infection group as compared to controls and Th17 cells in spleen from mice of H.pylori infection group were all obviously higher than that of control group;IL-17 mRNA,IL-23 mRNA and the ratio of Th17 cells in mice splenocyte of H.pylori infection group mice increased gradually with the time prolonged;The levels of both mRNA and protein levels of IL-17and IL-23 decreased significantly in the treatment group compared with pre-treatment;There was a positive correlation between IL-17 and IL-23 expression levels of mice gastric mucosa and gastric inflammation degree.Conclusion H.pylori infection induced the immune response of Th17 cells;The levels of IL-17 and IL-23 increased in gastric mucosa of mice after H.pyloriinfection;The degree of H.pylori-infected mice gastric inflammation was positive correlation with the levels of IL-17 and IL-23 of gastric mucosa.