Abstract: The purpose of this experiment was to study the changes in the main functional components of celery juice after fermentation and the effect of celery fermentation broth on the prevention and immunoregulation of dextran sodium sulfate (DSS) induced ulcerative colitis (UC) in mice. Fifty male 4-week-old C57BL/6 mice were randomly divided into blank group, model group, and low, medium, and high concentration of cetery fermentation broth groups, with 10 mice in each group. The mice in blank and model groups were given sterile normal saline, the others were given different concentrations of celery fermentation broth by gavage for 7 days, according to the dose standard of 10 μL/g BW. Beginning on the 8th day, except for the blank group to drink sterile water freely, the mice in other groups drunk 3% DSS solution for 7 days. During the induction process, the mice were weighed daily and scored by the disease activity index (DAI). On the 14th day, blood was obtained through the eyeball method, and then the mice were killed by dislocation of spine, and the colon tissue was taken to measure the length and made into pathological sections by the hematoxylin eosin (HE) staining method for histopathological analysis. CD4⁺ and CD8⁺ T lymphocyte ratios in peripheral blood of mice was detected by flow cytometry sorting technology. The serum levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interferon-γ (IFN-γ) and interleukin-10 (IL-10) were detected by enzyme-linked immunosorbent assay (ELISA). The results showed that:①After fermentation, the contents of various active ingredients such as total acid, total sugar, total polyphenols, flavonoids, vitamin C and superoxide dismutase (SOD) in celery juice increased significantly (P<0.05). ②Compared with the model group, high concentration group could reduce the weight loss (P<0.01), colon shortening (P<0.01) and DAI reduction (P<0.05) of mice induced by DSS. ③Histopathological analysis showed that the symptoms of UC in the fermentation broth groups were improved to varying degrees, the intestinal gland structure was relatively complete, the goblet cells were slightly reduced, and only a few lymphocytes and neutrophils were infiltrated. ④The results of flow cytometry analysis showed that CD4⁺/CD8⁺ T lymphocytes in the whole blood of the fermentation broth groups were increased (P<0.01) compared with the model group. ⑤The ELISA test results showed that the content of IL-6, TNF-α and IFN-γ in the fermentation broth groups were lower, and the content of IL-10 was higher than that of the model group (P<0.01). In summary, the main active components of celery juice after fermentation were generally higher than those of unfermented ones. Celery fermentation broth had preventive and immunoregulatory effects on DSS-induced UC in mice. The mechanism might be related to maintaining the balance of CD4⁺ and CD8⁺ T lymphocytes in the peripheral blood, inhibiting the expression of pro-inflammatory factors (IL-6, TNF-α and IFN-γ), and increasing the expression of anti-inflammatory factors (IL-10).

Key words: celery fermentation broth; dextran sodium sulfate; ulcerative colitis; disease activity index